Feature request: share binding for eval_visual and eval_under_cursor

[cprn]

Hi. Currently we can set two separate bindings for:

• evaluating a variable or expression under the cursor
• evaluating a visible selection

These two operations are in two separate modes (visual and normal) and therefore could share a binding leaving one more functional key free to do different things. It's a low priority as one can set them to, let's say, <f1> and <c-f1> but it'd be more convenient for vdebug to just understand which mode Vim is currently in.