chore: update docs

Signed-off-by: Aaron Pham <29749331+aarnphm@users.noreply.github.com>

tools/bazel

@@ -21,11 +21,10 @@ fi
 VERSION=${OVERRIDE_BAZEL_VERSION:-5.3.1}
 echo "INFO: Running bazel wrapper (see //tools/bazel for details), bazel version $VERSION will be used instead of system-wide bazel installation." >&2
 
-# update tools/update_mirror.sh to populate the mirror with new bazel archives
 BASEURL_MIRROR="https://storage.googleapis.com/grpc-bazel-mirror/github.com/bazelbuild/bazel/releases/download"
 BASEURL="https://github.com/bazelbuild/bazel/releases/download"
 pushd "$(dirname "$0")" >/dev/null
-# bazel binary will be downloaded to GRPC_REPO_ROOT/tools directory by default
+# bazel binary will be downloaded to GIT_ROOT/tools directory by default
 DOWNLOAD_DIR=${OVERRIDE_BAZEL_WRAPPER_DOWNLOAD_DIR:-$(pwd)}
 
 case $(uname -sm) in