- Updated `ScriptTagHelper` and `LinkTagHelper` to maintain their quotes on generated script tags.
- Removed `TagHelperOutputExtensions`. It's no longer needed.
- We no longer string replace quotes directly. We rely on encoding and the initial representation of an attribute to ensure quotes don't break generated attributes.
- Updated tests.
- Simplify things that used to rely on HtmlTextWriter. This behavior is
now the default.
- Simplify a whole mess of Razor TextWriter code.
- Integration test for merging of TagHelper buffers back into the 'main'
buffer.