[github] Change "code owners" note to refer to "maintainers" (#118087)

Author: DavidSpickett

.github/CODEOWNERS

@@ -7,10 +7,9 @@
 # to receive an approval from a "code owner" in particular -- any LLVM project
 # member can approve pull requests.
 #
-# Note that GitHub's concept of "code owner" is independent from LLVM's own
-# "code owner" concept, they merely happen to share terminology. See
-# https://llvm.org/docs/DeveloperPolicy.html#code-owners, as well as the
-# CODE_OWNERS.txt files in the respective subproject directories.
+# This is independent of LLVM's own "maintainer" concept.
+# See https://llvm.org/docs/DeveloperPolicy.html#maintainers as well as the
+# Maintainers.* files in the the respective subproject directories.
 
 /libcxx/ @llvm/reviewers-libcxx
 /libcxxabi/ @llvm/reviewers-libcxxabi