fix Issue 12900 - Wrong code in IfStatement condition Expression
[WS] Replace tab with spaces.

Tab was added in d8e5f55c9b94e831b6d178a20e34144933c3fc32.
Merge pull request #3694 from denis-sh/ws-fixup-pull-3687

[Whitespace] Replace tab with spaces.
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 #3685 from 9rnsr/fix12900

More conservative fix for issue 12900 - Wrong code in IfStatement condition Expression
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
Issue 10018 - Add VRP support for const/immutable variables
Merge pull request #3699 from lionello/bug10018

Issue 10018 - Add VRP support for const/immutable variables