Update issue templates (#8989)

* Update issue templates

* Update bug_report.md

* Update feature_request.md

* Update support.md

* Update feature_request.md

.github/ISSUE_TEMPLATE/bug_report.md

 ---
 name: Bug Report
-about: Create a report to help us improve
+about: If something isn't working as expected
 
 ---
 
-[Issue text goes here].
+<!-- Make sure that you are submitting a new bug that was not previously reported or already fixed -->
 
-* * * *
+<!-- Please use a concise and distinct title for the issue -->
 
-- [ ] I searched or browsed the repo’s other issues to ensure this is not a duplicate.
-- [ ] This bug happens on a [tagged release](https://github.com/tootsuite/mastodon/releases) and not on `master` (If you're a user, don't worry about this).
+### Expected behaviour
+
+<!-- What should have happened? -->
+
+### Actual behaviour
+
+<!-- What happened? -->
+
+### Steps to reproduce the problem
+
+<!-- What were you trying to do? -->
+
+### Specifications
+
+<!-- What version or commit hash of Mastodon did you find this bug in? -->
+
+<!-- If a front-end issue, what browser and operating systems were you using? -->

.github/ISSUE_TEMPLATE/feature_request.md

----
+--
 name: Feature Request
-about: Suggest an idea for this project
+about: I have a suggestion
 
 ---
 
-[Issue text goes here].
+<!-- Please use a concise and distinct title for the issue -->
+
+<!-- Consider: Could it be implemented as a 3rd party app using the REST API instead? -->
+
+### Pitch
+
+<!-- Describe your idea for a feature. Make sure it has not already been suggested/implemented/turned down before -->
 
-* * * *
+### Motivation
 
-- [ ] I searched or browsed the repo’s other issues to ensure this is not a duplicate.
+<!-- Why do you think this feature is needed? Who would benefit from it? -->

.github/ISSUE_TEMPLATE/support.md

+---
+name: Support
+about: Ask for help with your deployment
+
+---
+
+We primarily use GitHub as a bug and feature tracker. For usage questions, troubleshooting of deployments and other individual technical assistance, please use one of the resources below:
+
+- https://discourse.joinmastodon.org
+- #mastodon on irc.freenode.net