Merge branch '202335-docs-substitution-test' into 'master'

Docs: Create substitution word test for Vale

Closes #202335

See merge request gitlab-org/gitlab!24609

doc/.linting/vale/styles/gitlab/Substitutions.yml

+---
+# `extends` indicates the Vale extension point being used.
+# Full list of styles: https://errata-ai.github.io/vale/styles/
+extends: substitution
+
+# Substitution rules can display the matched and suggested strings in the 
+# message shown to the user. The first use of %s prints the suggested option,
+# and the second use of %s displays what was found in the text.
+message: Use "%s" instead of "%s."
+
+# Should a result be flagged as a suggestion, warning, or error?
+# Results that fall below the MinAlertLevel set in 
+# https://gitlab.com/gitlab-org/gitlab/blob/master/.vale.ini won't be shown.
+level: warning
+
+# Should a match be case-insensitive or case-sensitive?
+# Acceptable values are 'true' or 'false'
+ignorecase: true
+
+# Should this rule be limited to a specific scope? If yes, uncomment the line.
+# Possible scopes: https://errata-ai.github.io/vale/formats/#available-scopes
+# scope: heading
+
+# Should this rule ignore normal word boundaries, such as \b ?
+# Acceptable values are 'true' or 'false'
+nonword: true
+
+# What is the source for this rule?
+link: https://about.gitlab.com/handbook/communication/#top-misused-terms
+
+# The 'swap' section provides a list of values, one per line, in the form of
+# $bad: $good
+swap:
+  GitLabber: GitLab team member
+  self hosted: self-managed
+  self-hosted: self-managed