Feature request: Convert all in current selection

Hi! Thanks for creating this plugin!

It would be great to be able to convert all colors in the currently selected text. Thoughts?

Example:

You have a list of 3 colors but only want to convert the first two.
```
'#B84645'
'#61AEE1'
'#B1812C'
```

The result of selecting the first two colors and converting to rbg would be:
```
'rgb(184,70,69)'
'rgb(97,174,225)'
'#B1812C'
```

