chore: issue templates similar to lean4 repo

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,40 @@
+---
+name: Bug report
+about: Create a bug report
+title: ''
+labels: bug
+assignees: ''
+
+---
+
+### Description
+
+[Clear and concise description of the issue]
+
+### Context
+
+[Broader context that the issue occured in. If there was any prior discussion on [the Lean Zulip](https://leanprover.zulipchat.com), link it here as well.]
+
+### Steps to Reproduce
+
+1.
+2.
+3.
+
+**Expected behavior:** [Clear and concise description of what you expect to happen]
+
+**Actual behavior:** [Clear and concise description of what actually happens]
+
+### Versions
+
+[Version of vscode-lean4 (Hover over 'lean4' in the 'Extensions' menu)]  
+[Output of `lean --version` in the folder that the issue occured in]  
+[OS version]
+
+### Additional Information
+
+[Additional information, configuration or data that might be necessary to reproduce the issue]
+
+### Impact
+
+Add :+1: to [issues you consider important](https://github.com/leanprover/vscode-lean4/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc). If others are impacted by this issue, please ask them to add :+1: to it.

.github/ISSUE_TEMPLATE/rfc.md

@@ -0,0 +1,26 @@
+---
+name: Request for comments
+about: Create a feature proposal
+title: 'RFC: '
+labels: RFC
+assignees: ''
+
+---
+
+### Proposal
+
+Clear and detailed description of the proposal. Consider the following questions:
+
+  - **User Experience**: How does this feature improve the user experience?
+
+  - **Beneficiaries**: Which Lean users and projects benefit most from this feature/change?
+
+  - **Maintainability**: Will this change streamline code maintenance or simplify its structure?
+
+### Community Feedback
+
+Ideas should be discussed on [the Lean Zulip](https://leanprover.zulipchat.com) prior to submitting a proposal. Summarize all prior discussions and link them here.
+
+### Impact
+
+Add :+1: to [issues you consider important](https://github.com/leanprover/vscode-lean4/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc). If others benefit from the changes in this proposal being added, please ask them to add :+1: to it.