For #94637

Allows the active paramter to be be specified per signature instead of for all signatures. If provided, this overrides `SignatureHelp.activeParamter`

show names of formatting edits and code actions providers when they block save. also add links that links that open the settings editor for each feature, #90851

For #86788

Squashed commit of the following:

commit 2bbee1ef
Author: Pine Wu <octref@gmail.com>
Date:   Wed Jan 22 11:48:44 2020 +0100

    Separate testing changes

commit 047e81e9
Author: Pine Wu <octref@gmail.com>
Date:   Wed Jan 22 11:44:30 2020 +0100

    Tweak layout

commit 078b21f6
Author: Pine Wu <octref@gmail.com>
Date:   Tue Jan 21 15:20:07 2020 +0100

    UI changes

commit a869c0fa
Author: Pine Wu <octref@gmail.com>
Date:   Tue Jan 21 12:28:35 2020 +0100

    WIP

- extract a separate DocumentRangeSemanticTokensProvider that deals with a document range
- extract a separate provideDocumentSemanticTokensEdits that deals with updating via SemanticTokensEdits a previous result

For #86788