Add keymap field to bug report issue template (#44564)

Update the issue template used for "Report a bug" to include a field
specifically for the user's keymap file, as we've seen multiple cases
where we end up asking the users for their custom keymap, to ensure that
they're not overriding existing defaults.

Release Notes:

- N/A

.github/ISSUE_TEMPLATE/10_bug_report.yml

@@ -75,6 +75,22 @@ body:
         </details>
     validations:
       required: false
+  - type: textarea
+    attributes:
+      label: Relevant Keymap
+      description: |
+        Open the command palette in Zed, then type “zed: open keymap file” and copy/paste the file's contents.
+      value: |
+        <details><summary>keymap.json</summary>
+
+        <!-- Paste your keymap file inside the code block. -->
+        ```json
+
+        ```
+
+        </details>
+    validations:
+      required: false
   - type: textarea
     attributes:
       label: (for AI issues) Model provider details