Make the suggestion from history in prompt greyed out until activated

[xJonathanLEI]

Currently the history suggestion in prompts use the same color as any other text (it uses ui.text):

It can confuse new users as the cursor is place at the beginning of the seemingly active text. Even for experienced users it might not be immediately obvious whether the text is active or not (can only tell from he cursor position).

I suggest we use an alternative color when showing the suggestion. If this is desired, what color should we use? I would suggest using comment.

If this gets approved I will submit a PR. Thanks!

[xJonathanLEI]

Or should a new theme key be created for this? Btw this is how it looks like using comment on the default theme:

[xJonathanLEI]

Hmm or maybe I should just submit the PR first and let the discussion happen that together with the review process?

[gabydd]

Maybe a new theme key that falls back to comment if that key isn't present?

[xJonathanLEI]

How about a new theme key ui.prompt.suggestion?

[gabydd]

Maybe ui.prompt.completion your idea is good as well

[xJonathanLEI]

archseer suggested ui.text.inactive to be added and used here. Proceeding with that for the PR.