* Merging changes (from dev branch; doing manually to squash them really)of HTML Parser to be aware of HTML Comments so TagHelpers don't complain about comments as content.
- For older version of Razor the HTML comments will be complained about by TahHelperRewriter
- RazorParserFeatureFlags tests now ensure that AllowHtmlCommentsInTagHelpers is true in 2.1 version and false in older versions
- Added extra test for IsHtmlCommentAhead to make sure Razor code transition is allowed in comment tag
- Moved the unallowed html comment ending to a static array.
- Part of caching length required the `Span`'s `ReplaceWith` method to propagate its changes to its parent so that it can propogate the change to invalidate all parent length caches.
- Added Span and Block tests to validate the interaction of caching.
#1927
- Part of caching length required the `Span`'s `ReplaceWith` method to propagate its changes to its parent so that it can propogate the change to invalidate all parent length caches.
- Added Span and Block tests to validate the interaction of caching.
#1927
- Changed `DefaultRazorDiagnostic` to expose a little more information for tests. This info is only available when casted to the `DefaultRazorDiagnostic` type and only available internally.
- Changed parameter order of a `DefaultTagHelperTargetExtension` diagnostic.
- Updated baselines of files in `Razor.Language.Test`.
- Added a new convenience constructor on `SourceSpan`. The ctor is equivalent to calling the class with a SourceLocation.
#1827
- Prior to this when the partial parser would successfully parse a change we'd mutate the returned syntax tree so any data inquired about the tree would then be wrong. We now isolate mutations to copied versions of the syntax tree.
- Added copy tests to ensure that we were appropriately copying all the various syntax node types.
#1793
- Revived `RazorEditorParser`.
- Made `PartialParseResult` internal and renamed it to `PartialParseResultInternal`. This fell in line with other syntax tree types.
- Moved the `RazorEditorParser` implementation away from `TextChange` and `ITextBuffer`. Instead it now relies on `SourceChange` and the VS contract `ITextSnapshot`.
- Added `RazorEditorParserTest` to ensure the changes in implementation did not impact previous functionality.
- Removed some obvious tests that unnecessarily re-tested behavior that was already verified.
- Updated tests.
- Moved several Language.Test types to the common test project so they could be reused.
#1259