Remove reference to Homebrew tap pinning

Tap pinning is deprecated (Homebrew/brew#5925) in favor of using the fully qualified name.

Closes #8027.

PiperOrigin-RevId: 244838884
diff --git a/site/docs/install-os-x.md b/site/docs/install-os-x.md
index 8537383..aade362 100644
--- a/site/docs/install-os-x.md
+++ b/site/docs/install-os-x.md
@@ -94,7 +94,6 @@
 
 ```bash
 brew tap bazelbuild/tap
-brew tap-pin bazelbuild/tap
 brew install bazelbuild/tap/bazel
 ```