fix Issue 12967 - Prefix method 'this' qualifiers should be disallowed in DeclDefs scope
Check redundant/conflicting attributes between prefix and postfix
Fix another broken case of qualified anchors.

The previous fix didn't work for template members of templated structs.
Update ddoc test to expect fully-qualified symbols.
Fixup

Remove redundant braces.
Merge pull request #3689 from 9rnsr/fix12967

Issue 12967 - Prefix method 'this' qualifiers should be disallowed in DeclDefs scope
Merge pull request #3695 from quickfur/more_ddoc_anchors

DDOC fully-qualified anchors for template members of template structs/classes
[cleanup] Remove commented code in optimize.c
Add optimize methods for UnaExp and BinExp
Add const checking methods for UnaExp and BinExp
[refactor] Use const checking method for UnaExp and BinExp

Using a method for the const checking makes the code a bit easier to
read, as well as moves the const check implementation to a single piece
of code.
Unify optimize methods ...
Unify optimize methods ...
Unify optimize methods ...
Unify optimize methods ...
Unify optimize methods ...
Unify optimize methods ...
fixup! Add optimize methods for UnaExp and BinExp
Unify optimize methods ... multiple