Merge branch 'mjang-doc-vale-contraction-messages' into 'master'

Update Vale message on contractions

See merge request gitlab-org/gitlab!30631

doc/.vale/gitlab/Contractions.yml

@@ -3,7 +3,7 @@
 #
 # For a list of all options, see https://errata-ai.github.io/vale/styles/
 extends: substitution
-message: Use "%s" instead of "%s" in most cases.
+message: Use "%s" instead of "%s", for a friendly, informal tone.
 link: https://docs.gitlab.com/ee/development/documentation/styleguide.html#language
 level: suggestion
 nonword: false