Feature summary
CodeMirror enables completions for [[ and {{ when in source mode in WikiEditor. However, because of the way CodeMirror integrates with VE source modes, this doesn't work in the 2017 editor or DiscussionTools source mode.
CodeMirror's hands-off implementation with VE is for complicated reasons, and VE already has a completion system (see: \ and @) that could be used.
This is less important for the VE source modes than it was for WikiEditor because in the VE modes the keyboard shortcuts and toolbar actions are available to trigger the relevant inspector/dialog.
Codemirror also offers completions on < and __ for tags and magic words. These are less-available from VE shortcuts, because there's a fair few that we don't have specific integrations for.
Use case(s):
Quickly inserting links and templates.
Benefits:
Lets users avoid typos and quickly add links without needing to search elsewhere.
Tech/news
DiscussionTools' source mode and the 2017 wikitext editor now offer autocomplete for links ([[), templates ({{), HTML and parser tags (<), and magic words (__)."
