Parsing/Notes/Post Parsoid Changes

As part of work to make Parsoid the default wikitext engine, we added a whole lot of backward compatibility behavior that adds unnecessary complexity to Parsoid and is also questionable behavior for end-users. Once Parsoid becomes the default, we should start deprecating and removing these. Where necessary, provide linting / bot support.

• Deprecate Whitespace stripping after comments: T264921.
• Deprecate concept of rendering transparent nodes: T264919.
• Get rid of section wrapping special handling for b/c behavior with core parser ( see commit b652e479a48e8702984822018226077e017315b4 to fix T213468) and revert back to standard DOM semantics wrt section id assignments.
• Fix all the doBlockLevel madness: T134469.
• Deprecate use of 'parser' terminology since it is misleading.