Instruction Selection Highlighting

Selecting an instruction mnemonic highlights the entire line, operands and all. Selecting an operand highlights the specific operand as well as matches elsewhere on the display.

I think the former should behave like the latter, which is also how IDA does it. However, in IDA, I often lose my place when _every_ `mov` is highlighted so I think there's value in highlighting the entire line as well, but with a much lighter color.