Update build JSC script in CONTRIBUTING.md (#22162)

### What does this PR do?

Updates build instructions in `CONTRIBUTING.md`

### How did you verify your code works?

N/A

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

CONTRIBUTING.md

@@ -223,8 +223,8 @@ $ git clone https://github.com/oven-sh/WebKit vendor/WebKit
 $ git -C vendor/WebKit checkout <commit_hash>
 
 # Make a debug build of JSC. This will output build artifacts in ./vendor/WebKit/WebKitBuild/Debug
-# Optionally, you can use `make jsc` for a release build
-$ make jsc-debug && rm vendor/WebKit/WebKitBuild/Debug/JavaScriptCore/DerivedSources/inspector/InspectorProtocolObjects.h
+# Optionally, you can use `bun run jsc:build` for a release build
+$ bun run jsc:build:debug && rm vendor/WebKit/WebKitBuild/Debug/JavaScriptCore/DerivedSources/inspector/InspectorProtocolObjects.h
 
 # After an initial run of `make jsc-debug`, you can rebuild JSC with:
 $ cmake --build vendor/WebKit/WebKitBuild/Debug --target jsc && rm vendor/WebKit/WebKitBuild/Debug/JavaScriptCore/DerivedSources/inspector/InspectorProtocolObjects.h

test/internal/ban-limits.json

@@ -10,7 +10,7 @@
   ".stdDir()": 41,
   ".stdFile()": 18,
   "// autofix": 168,
-  ": [^=]+= undefined,$": 260,
+  ": [^=]+= undefined,$": 259,
   "== alloc.ptr": 0,
   "== allocator.ptr": 0,
   "@import(\"bun\").": 0,
@@ -38,7 +38,7 @@
   "std.fs.cwd": 104,
   "std.log": 1,
   "std.mem.indexOfAny(u8": 0,
-  "std.unicode": 33,
+  "std.unicode": 27,
   "undefined != ": 0,
   "undefined == ": 0,
   "usingnamespace": 0