Improve code gen for localgot
convert escape mask literal constant to ESCAPEmask
fix Issue 9726 - Add minimum % coverage required for -cov testing
Fixes Issue 6089 - extern variable should not have an initializer.
Merge pull request #1759 from WalterBright/fix9726

fix Issue 9726 - Add minimum % coverage required for -cov testing
Merge pull request #1752 from WalterBright/improvelocalgot

Improve code gen for localgot
Merge pull request #1762 from AndrejMitrovic/Fix6089

Issue 6089 - extern variable should not have an initializer.
Merge pull request #1757 from braddr/backend-escape

convert escape mask literal constant to ESCAPEmask
Merge pull request #1760 from 9rnsr/fix_ast_identity

Add assertion and fix AST identity that had broken by template instantiation
fix Issue 9713 - Ddoc: Empty description suppress automatic example generation

Even if proper description is empty, generated examples should be appeared
fix Issue 9714 - Ddoc: Combination of -D and -unittest reveals hidden unittest function

Even if -unittest is specified, hidden function should not be appeared in ddoc output
Refinement for #1641

- Reuse unindent mechanism that has introduced by #1377
- Remove trailing whitespace from auto-generated ddoc example
fix Issue 9757 - Ddoc: documented unittest after ditto should work