v0.900.8

This release upgrades @angular/language-service to v9.0.0-rc.12.
For a complete change log see here.

New features:

• completions for output $event properties in (#34570) (2a53727)
• provide completion for $event variable (#34570) (c246787)
• provide hover for microsyntax in structural directive (#34847) (baf4a63)

Bug fixes:

• prune duplicate returned definitions (#34995) (71f5417)
• remove repeated symbol definitions for structural directive (#34847) (35916d3)
• warn, not error, on missing context members (#35036) (0e76821)
• enable debug mode only when it is strictly turned on