Ability to combine 'dotnet format whitespace' and 'dotnet format style' in a single run

## Background and Motivation

Reformatting code with `dotnet format` without running 3rd party analyzers/fixers needs 2 separate runs (`dotnet format whitespace` and `dotnet format style`)
It would be nice to be able to combine the subcommands in order to avoid the cost (on solutions with more costly builds).

So the motivation is foremost the perf (we have cases where we need to iteratively change the code and run dotnet format comamnds - in one specific case over 1 hour is spent in `dotnet format` runs in couple hours long pipeline - being able to slash the the `dotnet format` cost by half - via merging the 2 subcommands in single run - we'd save >10% of runtime in such case).

## Perceived priority

Nice to have

## Proposed CLI & Usage Examples

Either a new subcommand combining `style` and `whitespace`:

`dotnet format builtin`

Or ability to combine subcommands:

`dotnet format --mode style --mode whitespace`

## Risks

Complicating the existing CLI