_Generic(..., const:...) example
Extension: trailing return type
Example of attributes on trailing return function type
Example of auto needed as a specifier, not store
parse_type() handles trailing return type

This moves the trailing return logic to type parsing instead of
decl parsing.
Remove check_trailing_return() - moving to type parsing
Move trailing return logic into parse_type_declarator

This means both decl and type parsing can handle
trailing return types.
Merge branch 'master' into feature/trailing-return-type

This brings in type printing fixes needed in trailing return type tests.

Conflicts:
	src/cc1/parse_type.c
Add trailing return type to type printing test
Trailing return parses using just-parsed function type
Trailing return type tests
rm auto-specifier.c
Preserve attributes and locations on trailing types
Clarify parse_type()'s use of parse_at_decl()
Merge branch 'feature/trailing-return-type'

Conflicts:
	src/cc1/type_nav.c
type_is_primitive_anysign() handles char properly
Prevent constexpr dereference of strings through non-char *
Minor factorisation in cast logic
Fix funcargs retaining on trailing return construction
Continue-after-error on too few arguments