Centralize Zed.log documentation (#40808)

Just wanted a single location to point people to for telling them where
to find their log file. I left duplicate text in GitHub Issue templates,
as it seems annoying to have to follow a link when making an issue.

Release Notes:

- N/A

docs/src/SUMMARY.md

@@ -9,6 +9,7 @@
 - [Windows](./windows.md)
 - [Telemetry](./telemetry.md)
 - [Workspace Persistence](./workspace-persistence.md)
+- [Troubleshooting](./troubleshooting.md)
 - [Additional Learning Materials](./additional-learning-materials.md)
 
 # Configuration