Remove out from .gitignore. NFC

The `build-js.sh` script was removed back in #2464.

Author: sbc100

.gitignore

@@ -11,7 +11,7 @@ tags
 # generated by Abseil when building fuzztest
 options-pinned.h
 
-# File generated by build-js.sh
+# Files generated by test suite and fuzzer
 /out/
 
 # files related to building in-tree