Option to set background color of bookmarked lines

[ibraimgm]

The option decorateWholeLine, when true, paints the entire line of the color specified by lineDecoratorColor. The default color is a softer version of the bookmark icon color.

Take a look:

[Rah1x]

Awesome buddy.. did you already merge and release the work? Cause on vscode the last version ive got is [0.12.0] - 2018-09-14.

[ibraimgm]

@Rah1x Nope, just sent the PR. Now we need to wait for @alefragnani to review the work and, if it is good enough, do the merge.

[alefragnani]

Hi @ibraimgm ,

Thank you for another PR. It will be really useful 👍

I just remembered there is another PR for the same request for my other Bookmarks extension alefragnani/vscode-bookmarks#133. I still didn't merge that (other priorities) but I want to start merging all PRs (including yours) starting next week.

Both PRs use a different approaches and, I think you could simplify this one, if you use just one setting, called backgroundLineColor (instead of lineDecoratorColor). If empty, it means no background color.

Could you update your PR with this idea? I will try to release an extension's update in the next week.

Thank you

[ibraimgm]

Done!