[enhancement]: basic markdown functionality in input fields

[codedealer]

Is your feature request related to a problem? Please describe.
Currently all the mark up for prompts is done manually, it would be nice to have ui handle routine things like closing md tags, wrapping user provided text in tags.

Describe the solution you'd like
A simple handler for markdown enabled text fields (prompt inputs throughout the app, memory books, etc.). Basic features would include:

1. Shortcut support:
   1.1. ctrl + B to wrap the selected text in ** tags
   1.2 ctrl + I to wrap the selected text in * tags
   1.3 ctrl + / to wrap in HTML comment <!-- since it apparently a neat way of discreetly instructing a model hidden from user
   1.4 (something else?)
2. Type assistance which I think can be especially useful on mobile devices:
   2.1. When a user puts an opening tag automatically provide a closing tag after the cursor position (given there is no text there) mimicking behavior observed in most code editors
   2.2 this type of validation maybe useful when evaluating dangling tokens in responses as well? (Feature Enhancement: Improve "Trim Incomplete Sentences" detection. #824)

Describe alternatives you've considered
An alternative would be to hook up a full fledged markdown editor but I think this is excessive given the most common use case where only the basic markdown features are used.

Additional context
If approved I am willing to work on implementing it.