[clang] [clang-format] Add `SpaceInComments` option to control spacing around `/* */` (PR #162105)

[via cfe-commits]

owenca wrote:

> * Add a clang-format `SpaceInComments` option to control spaces right after `/*` and right before `*/` in block comments.

We should name the option `SpacesInComments`, similar to `SpacesInAngles` and other `SpacesIn...` options.

> * The option has four per-position settings inside `SpaceInComments`. Each setting accepts `Always`, `Never`, or `Leave`.
>   
>   * `AfterOpeningComment` and `BeforeClosingComment` for regular block comments.
>   * `AfterOpeningParamComment` and `BeforeClosingParamComment` for inline parameter comments such as `/*param=*/`.

When I suggested "to add a single `SpacesInBlockComment` option", I didn't mean to add it on top of those suboptions. Instead, `SpacesInBlockComment` should function like `SpacesInAngles` for example.

https://github.com/llvm/llvm-project/pull/162105