[docs] Change Gitter to Spectrum (#14558)

* [docs] Change gitter to spectrum

* Add a notification

* Update notifications.json

* Remove unintended hard wraps

.github/ISSUE_TEMPLATE/3.support.md

@@ -1,15 +1,15 @@
 ---
 name: Support
-about: I need support with Material-UI
+about: I need support with Material-UI.
 ---
 
 --------------^ Click "Preview" for a nicer view!
 
-We primarily use GitHub as an issue tracker; for usage and support questions, please check out these resources below. Thanks!
+We primarily use GitHub as an issue tracker. For usage and support questions, please check out the resources below. Thanks!
 
 ---
 
-1. Read the documentation: https://material-ui.com/.
-2. Ask questions on StackOverflow using the tag material-ui: https://stackoverflow.com/questions/tagged/material-ui.
-3. Chat with the community on Gitter: https://gitter.im/mui-org/material-ui.
-4. Ping us on Twitter: https://twitter.com/MaterialUI.
+1. Read the [documentation](https://material-ui.com/).
+2. Ask questions on [StackOverflow](https://stackoverflow.com/questions/tagged/material-ui) using the tag material-ui.
+3. Chat with the community on [Spectrum](https://spectrum.chat/material-ui).
+4. Ping us on [Twitter](https://twitter.com/MaterialUI).

.github/ISSUE_TEMPLATE/4.support-us.md

@@ -1,6 +1,6 @@
 ---
-name: 🤝 Support us on Material-UI
-about: If you would like to support our efforts in maintaining this community-driven project 🙌!
+name: 🤝 Support Material-UI development
+about: I'd like to help with maintaining this community-driven project 🙌!
 ---
 
 --------------^ Click "Preview" for a nicer view!
@@ -14,13 +14,13 @@ Material-UI is an MIT-licensed open source project. It's an independent project
 
 ---
 
-As a group of volunteers you can help us in a few ways
+As a group of volunteers you can help us in a few ways:
 
-- Giving developer time on the project. (Message us on [Twitter](https://twitter.com/MaterialUI) or [Gitter](https://gitter.im/mui-org/material-ui) for guidance).
-Companies should be paying their employees to contribute back to the open source projects they use everyday.
-- Giving funds by becoming one of our sponsors/donators!
+- Giving developer time on the project. (Message us on [Twitter](https://twitter.com/MaterialUI) or [Spectrum](https://spectrum.chat/material-ui) for guidance).
+(Companies should be paying their employees to contribute back to the open source projects they use every day.)
+- Giving funds by becoming one of our sponsors / backers!
 
 If you'd like to sustain the future of the project as a whole, we have an [Open Collective](https://opencollective.com/material-ui) that you can donate to.
 This is a way for funds to be allocated to the core team.
 
-You can also support [Olivier](https://github.com/oliviertassinari) a this [Patreon](https://www.patreon.com/oliviertassinari).
+You can also support [Olivier](https://github.com/oliviertassinari) via [this Patreon page](https://www.patreon.com/oliviertassinari).

GOVERNANCE.md

@@ -34,7 +34,7 @@ also contribute in the following ways.
 
 - Support new users by answering questions on
 [StackOverflow](https://stackoverflow.com/questions/tagged/material-ui) and
-[Gitter](https://gitter.im/mui-org/material-ui).
+[Spectrum](https://spectrum.chat/material-ui).
 - Reviewing and commenting on [existing pull requests](https://github.com/mui-org/material-ui/pulls)
 and [issues](https://github.com/mui-org/material-ui/issues).
 - Reporting bugs or missing features by [creating an issue](https://github.com/mui-org/material-ui/issues/new).
@@ -78,7 +78,7 @@ In addition to their participation as a committer, Core Team members have the fo
 - Owner access to [mui-org on GitHub](https://github.com/mui-org).
 - Admin access to various tools and services ([npm](https://www.npmjs.com/package/@material-ui/core),
 [CircleCi](https://circleci.com/gh/mui-org/material-ui),
-[BrowserStack](https://www.browserstack.com/), [Gitter](https://gitter.im/mui-org/material-ui)).
+[BrowserStack](https://www.browserstack.com/), [Spectrum](https://spectrum.chat/material-ui)).
 - Admin access to all financial accounts.
 - Vote on the removal of committers and Core Team members.
 - Vote on decisions when consensus cannot be reached by the community.

README.md

@@ -11,7 +11,7 @@
 [![npm package](https://img.shields.io/npm/v/@material-ui/core/latest.svg)](https://www.npmjs.com/package/@material-ui/core)
 [![npm downloads](https://img.shields.io/npm/dm/@material-ui/core.svg)](https://www.npmjs.com/package/@material-ui/core)
 [![CircleCI](https://img.shields.io/circleci/project/github/mui-org/material-ui/next.svg)](https://circleci.com/gh/mui-org/material-ui/tree/next)
-[![Gitter](https://img.shields.io/badge/gitter-join%20chat-f81a65.svg)](https://gitter.im/callemall/material-ui?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Join the community on Spectrum](https://withspectrum.github.io/badge/badge.svg)](https://spectrum.chat/material-ui)
 [![Coverage Status](https://img.shields.io/codecov/c/github/mui-org/material-ui/next.svg)](https://codecov.io/gh/mui-org/material-ui/branch/next)
 [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/1320/badge)](https://bestpractices.coreinfrastructure.org/projects/1320)
 ![Code style](https://img.shields.io/badge/code_style-prettier-ff69b4.svg)

SUPPORT.md

@@ -2,7 +2,7 @@
 
 ## Asking Questions
 
-For how-to questions and other non-issues, please use [StackOverflow](http://stackoverflow.com/questions/tagged/material-ui) or [Gitter](https://gitter.im/callemall/material-ui) chat instead of Github issues. There is a StackOverflow tag called "material-ui" that you can use to tag your questions.
+For how-to questions and other non-issues, please use [StackOverflow](http://stackoverflow.com/questions/tagged/material-ui) or [Spectrum](https://spectrum.chat/material-ui) chat instead of Github issues. There is a StackOverflow tag called "material-ui" that you can use to tag your questions.
 
 ## Opening an Issue
 

docs/notifications.json

@@ -37,5 +37,9 @@
     "id": 40,
     "text": "Let's translate! <a style=\"color: inherit;\" target=\"_blank\" rel=\"noopener\" data-ga-event-category=\"l10n\" data-ga-event-action=\"notification\" data-ga-event-label=\"ja\" href=\"https://translate.material-ui.com/\">コミュニティがドキュメントを日本語に翻訳するのを手伝ってください</a>. 🇯🇵",
     "userLanguage": "ja"
+  },
+  {
+    "id": 41,
+    "text": "Come and join us in <a style=\"color: inherit;\" target=\"_blank\" rel=\"noopener\" href=\"https://spectrum.chat/material-ui\">the new Material-UI community</a> on Spectrum!"
   }
 ]

docs/src/pages/discover-more/community/community.md

@@ -2,7 +2,7 @@
 
 <p class="description">If you want to stay up to date on the development of Material-UI or to reach out to the community, you can follow those resources.</p>
 
-- Chat with us on [Gitter](https://gitter.im/mui-org/material-ui).
+- Chat with us on [Spectrum](https://spectrum.chat/material-ui).
 - For help using Material-UI, ask on StackOverflow using the tag
 [material-ui](https://stackoverflow.com/questions/tagged/material-ui).
 - Follow [@MaterialUI](https://twitter.com/MaterialUI) on Twitter.

docs/src/pages/getting-started/faq/faq.md

@@ -142,7 +142,7 @@ There are many ways to support Material-UI:
 - Improve [the documentation](https://github.com/mui-org/material-ui/tree/next/docs).
 - Help others to get started.
 - [Spread the word](https://twitter.com/MaterialUI).
-- Answer [StackOverflow questions](https://stackoverflow.com/questions/tagged/material-ui) or [issues marked as question](https://github.com/mui-org/material-ui/issues?q=is%3Aopen+is%3Aissue+label%3Aquestion) in the repository.
+- Answer questions on [StackOverflow](https://stackoverflow.com/questions/tagged/material-ui) or on [Spectrum](https://spectrum.chat/material-ui).
 
 If you use Material-UI in a commercial project and would like to support its continued development by becoming a **Sponsor**,
 or in a side or hobby project and would like to become a backer, you can do so through [OpenCollective](https://opencollective.com/material-ui).