Add Attached property used as hint for application to enabled or disable spellchecking.
Use in network/neochat!297 (merged) and qqc2-desktop-style!74 (merged)
Require: sonnet!25 (merged)
Use in network/neochat!297 (merged) and qqc2-desktop-style!74 (merged)
Require: sonnet!25 (merged)