(required for 'suspend' on functional types).
TYPE_REFERENCE element now has MODIFIER_LIST child, which hosts annotations and modifiers for the corresponding type reference.
Annotations and modifiers written before an extension function type are now parsed as annotations and modifiers for the functional type, not the receiver type.
So, '@Ann A.(B) -> C' was '(@Ann A).(B) -> C', and became '@Ann (A.(B) -> C)'.
NB: DSL_SCOPE_VIOLATION testData updated accordingly.
Type projection variance modifiers ('in', 'out') belong to a separate modifier list under corresponding type projection (not under a type reference).
'A<in suspend T>' is 'A<(in (suspend T))>', 'A<suspend in T>' is an error.
In stub builder, create a modifier list node to host annotations and modifiers (none so far; TODO properly serialize/deserialize types with modifiers).
Fix a problem where deleting last import directive via "optimize imports" could lead to incorrect psi structure resulting in CCE, see EA-64291
New imports are inserted at the head (after package directive if present) of the file (before any comments) if no imports were present
Add test for inserting import to file where a first statement is a comment
Drop code dealing with non-existing import list in ImportInsertHelperImpl
AbstractQuickFixTest: check for unexpected actions before changes to the file are made as it relies on the first line having specific format