ci: exclude "docs" commit type from minBodyLength commit message validation (#37764)

docs commits are sometimes trivial (e.g. an obvious typo fix) and in such cases its very
akward to to write up 100 chars worth of text about why this typo fix is the best thing in the
world and why it is so important and crucial that we must know why we are fixing the typo
at all. After all most typos are not just typos. Or are they? We'll shall see...

PR Close #37764

.ng-dev/config.ts

@@ -4,6 +4,7 @@ import {MergeConfig} from '../dev-infra/pr/merge/config';
 const commitMessage = {
   'maxLength': 120,
   'minBodyLength': 100,
+  'minBodyLengthExcludes': ['docs'],
   'types': [
     'build',
     'ci',