chore: update GitHub issue templates to focus on bugs (#2017 by @coolsoftwaretyler)

To priorize stability of the project, we should encourage folks to
use the issue tracker solely for bug reports, and funnel other items
to the GitHub discussions board.

Author: coolsoftwaretyler

.github/ISSUE_TEMPLATE/bug-report.md

@@ -1,22 +1,24 @@
 ---
 name: Bug report
 about: I think something is not working as it should
-
 ---
 
 <!-- Not following the template might result in your issue being closed without further notice -->
 
 **_Bug report_**
 
-* [ ] I've checked documentation and searched for existing issues
-* [ ] I've made sure my project is based on the latest MST version
-* [ ] Fork [this](https://codesandbox.io/s/y64pzxj01) code sandbox or another minimal reproduction. 
+-   [ ] I've checked documentation and searched for existing issues [and discussions](https://github.com/mobxjs/mobx-state-tree/discussions)
+-   [ ] I've made sure my project is based on the latest MST version
+-   [ ] Fork [this](https://codesandbox.io/s/y64pzxj01) code sandbox or another minimal reproduction.
 
 **Sandbox link or minimal reproduction code**
+
 <!-- link to your sandbox or alternatively minimal reproduction code-->
 
 **Describe the expected behavior**
+
 <!-- What should happen? -->
 
 **Describe the observed behavior**
+
 <!-- What happens instead? -->

.github/ISSUE_TEMPLATE/conceptual-question.md

@@ -1,16 +1 @@
-I have:
-
-* [ ] A conceptual question. 
-  * [ ] I've checked documentation and searched for existing issues
-  * [ ] I tried [GitHub Discussions](https://github.com/mobxjs/mobx-state-tree/discussions) first
-* [ ] I think something is not working as it should.
-  * [ ] I've checked documentation and searched for existing issues
-  * [ ] I've made sure your project is based on the latest MST version
-  * [ ] Fork [this](https://codesandbox.io/s/jlnmjqr7xv) code sandbox or another minimal reproduction. 
-  * [ ] Describe expected behavior
-  * [ ] Describe observed behavior
-* [ ] Feature request
-   * [ ] Describe the feature and why you feel your feature needs to be generically solved inside MST
-   * [ ] Are you willing to (attempt) a PR?
-   
-_Not following the above template might result in your issue being closed without further notice_
+**If your issue isn't a bug report, please consider using discussion threads instead of opening an issue: https://github.com/mobxjs/mobx-state-tree/discussions**