Make PR template a bit more helpful. (#1238)

* Make PR template a bit more helpful.

Clean up some typos, and point to an example docs folder in the go repo
rather than just the external docs hosted on our site.

* Fix typo.

* Agh, formatting.

.github/pull_request_template.md

@@ -1,22 +1,28 @@
-If you're making a doc PR or something tiny where the below is irrelevant, just delete this template and use a short description.
+If you're making a doc PR or something tiny where the below is irrelevant, just delete this
+template and use a short description.
 
 ### PR Structure
 
-* [ ] This PR has reasonably narrow scope (if not, break it down into smaller PRs)
-* [ ] This PR avoids mixing refactoring changes with feature changes (split into two PRs otherwise)
-* [ ] This PR's title starts with name of package that is most changed in the PR, ex. `services/friendbot`
-
+* [ ] This PR has reasonably narrow scope (if not, break it down into smaller PRs).
+* [ ] This PR avoids mixing refactoring changes with feature changes (split into two PRs
+  otherwise).
+* [ ] This PR's title starts with name of package that is most changed in the PR, ex.
+  `services/friendbot`
 
 ### Thoroughness
 
 * [ ] This PR adds tests for the most critical parts of the new functionality or fixes.
-* [ ] I've updated any docs ([developer docs](https://www.stellar.org/developers/reference/), `.md` files, etc...) affected by this change
+* [ ] I've updated any docs ([developer docs](https://www.stellar.org/developers/reference/), `.md`
+  files, etc... affected by this change). Take a look in the `docs` folder for a given service,
+  like [this one](https://github.com/stellar/go/tree/master/services/horizon/internal/docs).
 
 ### Release planning
 
-* [ ] I've updated the relevant CHANGELOG ([here](services/horizon/CHANGELOG.md) for Horizon) if needed with deprecations, added features, breaking changes, and DB schema changes
-* [ ] I've decided if this PR requires a new major/minor version according to [semver](https://semver.org/), or if it's monly a patch change. The PR is targeted at the next release branch if it's not a patch change.
-
+* [ ] I've updated the relevant CHANGELOG ([here](services/horizon/CHANGELOG.md) for Horizon) if
+  needed with deprecations, added features, breaking changes, and DB schema changes.
+* [ ] I've decided if this PR requires a new major/minor version according to
+  [semver](https://semver.org/), or if it's mainly a patch change. The PR is targeted at the next
+  release branch if it's not a patch change.
 
 ## Summary