* Add a synced use enhanced color checkbox to C# and Basic advanced options.

* Use optionstore in DiagnosticWindow option pages

* Add option search keywords for enhanced color option

This is a reworked version of #32616 targeting the dev16.0-preview3 branch.

Implementation of the custom column support has been kept extensible, so that each reference item can have customized key-values info, where key corresponds to the name of the custom dynamic column and values are set of one or more values the table entry. Columns become dynamically visible if at least one row in the table has a value for it.

Fixes #24877

This ports https://github.com/dotnet/roslyn/pull/28472, that went into the `editorconfig-ide` feature branch, into `dev16.0.x` branch with following additional refactorings/enhancements:

1. Generated .editorconfig file has all localized string as comments.
2. No hardcoding of individual options in the editorconfig file generator. Instead, each `EditorConfigStorageLocation` now requires to provide a delegate to convert a given option value into the .editorconfig string representation (basically complimentary of the parsing delegate that was already required).
3. Introduce concept of `OptionGroup` to enable grouping options in the same feature (such as CodeStyleOptions, CSharpCodeStyleOptions, FormattingOptions, CSharpFormattingOptions, etc.) into sub-features or groups (such as "this. preferences", "expression-level preferences", etc.). This enables the editorconfig generation to group the related options, without explicit knowledge of each option group.
4. Expose `AllOptions` from each option feature (such as CodeStyleOptions, CSharpCodeStyleOptions, FormattingOptions, CSharpFormattingOptions, etc.), so that the corresponding `IOptionProvider` always stays in sync with implemented options.

1. Break the analyzer into two separate diagnostics for flagging unused and unread members. Latter rule has no code fix.
2. Remove all UI option elements for the added diagnostics and turn the rules off by default for now.
3. Bail out for invalid operations and syntax errors.
4. Handle doc comments and nameof - report unread member diagostics instead of unused member diagnostics if referenced in non-read/write context.

Analyzer flags two cases: members with no read/writes and members with only writes.

1. Members with no read or writes: `Type '{0}' has an unused private member '{1}' which can be removed.`
2. Only writes: `Type '{0}' has a private member '{1}' which can be removed as the value assigned to it is never used.`

Code fix removes the unused member declaration.
Fixes #24225

Open questions:
1. Current analyzer design uses a single code style option for all members and both the above kinds of unused members. We can potentially have multiple options, but this should probably be done based on feedback.
2. Should the analyzer use different diagnostic IDs for the above two kinds of unused members? This will mean that the FixAll experience will need multiple iterations for removing unused members.
3. Should we update the code fix (or have an additional code fix) that also updates the write references for the case (2) above? Or is it better to leave the references to break the code so the user can analyze if the value being assigned can also be removed. The PR current chooses the latter approach as it is more conservative and unlikely to cause silent breaks.

These are missing languages which production team delivered today.

* Change goldbar text for updating keyboard bindings

* Fix text placeholder

* Update text

Fixes #27038

Add features to offer using conditional expressions ```?:``` over explicit if-statement flows. (#26236)