Auto merge of #23686 - saschanaz:git-ignore, r=jdm

Ignore VSCode IDE files

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This ignores launch.json (to configure debugger) and `ipch/` (for IntelliSense).

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #___ (GitHub issue number if applicable)

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- [x] These changes do not require tests because it only changes gitignore.

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.gitignore

@@ -40,7 +40,7 @@ capture_webrender/
 
 # VSCode
 .vscode
-!/.vscode
+!/.vscode/extensions.json
 
 /unminified-js