build: correct Xcode spelling in .gitignore

PR-URL: #38895
Reviewed-By: Michaël Zasso <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Darshan Sen <[email protected]>
Reviewed-By: Zijian Liu <[email protected]>
Reviewed-By: James M Snell <[email protected]>

.gitignore

@@ -117,7 +117,7 @@ tools/*/*.i.tmp
 /build
 /coverage
 
-# === Rules for XCode artifacts ===
+# === Rules for Xcode artifacts ===
 *.xcodeproj
 *.xcworkspace
 *.pbxproj