Problem/Motivation
The documentation in Form API's EntityAutocomplete class, of what properties are allowed in different configuration arrays, is difficult to find. Some properties are described in method docblocks; some on the class docblock; other docblocks are incomplete.
Proposed resolution
Rewrite inline documentation for EntityAutocomplete and DefaultSelection to clarify what property keys are permitted in config arrays:
* Move explanation of common config properties to class-level docblocks.
* Reference these in method level docblocks, to avoid duplication.
* Expand descriptions of properties where appropriate.
* Two classes to reference each other with @see, to avoid duplication.
Remaining tasks
Approve this issue summary change.
User interface changes
None.
API changes
None.
Data model changes
None.