[Refactoring] Rename Dsymbol::inTemplateInstance to isInstantiated

Because `inTemplateInstance` is too similar to `isTemplateInstance`.
fix Issue 10329 - Attributes not inferred for indirectly templated methods
Do not infer attributes for __xopEquals and __xopCmp
List internal names in idgen.c
Merge pull request #2832 from 9rnsr/fix10329

Issue 10329 - Attributes not inferred for indirectly templated methods