Note git fsmonitor in documentation for iOS also

Bug: None
Change-Id: Ib7e6b10965b9bcd5c4b51e3119ce3c3471699567
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4573501
Reviewed-by: Avi Drissman <[email protected]>
Auto-Submit: Tiago Vignatti <[email protected]>
Commit-Queue: Avi Drissman <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1150320}
diff --git a/docs/ios/build_instructions.md b/docs/ios/build_instructions.md
index 75b37246..ca3dc8c 100644
--- a/docs/ios/build_instructions.md
+++ b/docs/ios/build_instructions.md
@@ -481,6 +481,15 @@
 $ git update-index --untracked-cache
 ```
 
+#### Configure git to use fsmonitor
+
+If `git --version` reports 2.37 or higher, use fsmonitor, which will
+significantly speed git:
+
+```shell
+$ git config core.fsmonitor true
+```
+
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