Add a variable to disable highlight attributes

[FlorianeEnnaji]

Hello!
I added a variable called forceNoHighlightAttributes to disable the highlighting of the string found in each item. It also prevents the workaround advised in #34 or #67.
I'm happy to discuss this.

[apasccon]

Hey @FlorianeEnnaji!, I really appreciate your suggestion!.

In my opinion would be better this behavior:

• If you set the theme manually, then the library shall apply the same font size to the highlighted attributes by default (I guess this is the more common situation)
• If you just want to avoid highlighting attributes, you can always set this attributes the same as the theme's font attributes

What do you think about it?

[FlorianeEnnaji]

@apasccon Is that what you were thinking?