Improve "Attach to Host Process" menu flow

[daviwil]

This change improves the flow of the "Attach to Host Process" menu when
the language service hasn't started yet. It also changes the text display
slightly.

Here's a screenshot of the updated menu items:

[daviwil]

@rkeithhill let me know what you think about the text changes in the menu items. I noticed that the "detail" text was getting right-aligned for some weird reason, not sure if VS Code decided to do that somehow. I changed it to put everything in the description field so that it's more uniform.

[rkeithhill]

LGTM! Glad you figured out a better way to handle the not-initialized case! BTW, can you verify that search in the quick pick works on the pid, as well as title and process name.

[daviwil]

I learned some new things about Promises today, I can tell you that much ;) Yep, searching by pid works perfectly. Thanks Keith!