Add issue and PR templates (#41)

Author: charliermarsh

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,10 @@
+<!--
+Thank you for taking the time to report an issue! We're glad to have you involved with Ruff.
+
+If you're filing a bug report, please consider including the following information:
+
+* A minimal code snippet that reproduces the bug.
+* The current Ruff settings (any relevant sections from your `pyproject.toml`).
+* The current Ruff version (`ruff --version`).
+* A description of your environment (e.g., operating system, Python version, etc.).
+-->

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,15 @@
+<!--
+Thank you for contributing to Ruff! To help us out with reviewing, please consider the following:
+
+- Does this pull request include a summary of the change? (See below.)
+- Does this pull request include a descriptive title?
+- Does this pull request include references to any relevant issues?
+-->
+
+## Summary
+
+<!-- What's the purpose of the change? What does it do, and why? -->
+
+## Test Plan
+
+<!-- How was it tested? -->