Adds TextSubstitutionPolicy/TextCompletionPolicy/WritingToolsPolicy to
MarkdownEditorConfiguration (previously hardcoded AppKit calls with no
config surface). Outline's existing synced smartText preference now
actually drives smart quotes/dashes. Autocomplete and Writing Tools
get new local-only Settings -> Editor toggles (writingToolsBehavior
was already on unconditionally with no way to turn it off).
Puranjay Savar Mattas
b60e7ec94e