github: update issue templates (#2552)

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,36 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: A-tokio, C-bug
+assignees: ''
+
+---
+
+**Version**
+List the versions of all `tokio` crates you are using. The easiest way to get
+this information is using `cargo-tree`.
+
+`cargo install cargo-tree`
+(see install here: https://github.com/sfackler/cargo-tree)
+
+Then:
+
+`cargo tree | grep tokio`
+
+**Platform**
+The output of `uname -a` (UNIX), or version and 32 or 64-bit (Windows)
+
+**Description**
+Enter your issue details here.
+One way to structure the description:
+
+[short summary of the bug]
+
+I tried this code:
+
+[code sample that causes the bug]
+
+I expected to see this happen: [explanation]
+
+Instead, this happened: [explanation]

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,20 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: A-tokio, C-feature-request
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.

.github/ISSUE_TEMPLATE/question.md

@@ -0,0 +1,16 @@
+---
+name: Question
+about: Please use the discussions tab for questions
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+Please post your question as a discussion here:
+https://github.com/tokio-rs/tokio/discussions
+
+
+You may also be able to find help here:
+https://discord.gg/tokio
+https://users.rust-lang.org/

.github/PULL_REQUEST_TEMPLATE.md

@@ -5,6 +5,9 @@ the requirements below.
 Bug fixes and new features should include tests.
 
 Contributors guide: https://github.com/tokio-rs/tokio/blob/master/CONTRIBUTING.md
+
+The contributors guide includes instructions for running rustfmt and building the
+documentation, which requires special commands beyond `cargo fmt` and `cargo doc`.
 -->
 
 ## Motivation