add support for searching via regex

[MartinquaXD]

Problem
When searching through code bases having the ability to search file contents with a regex is invaluable and an important feature that telescope has over television.

Feature
television should have a CLI argument that enables support for regexes as the search string.

Examples
When you need to find all implementations of a specific trait just searching for the trait will also show everywhere it's only imported. To narrow down my search I'd have to do something like: impl.*<TRAIT_NAME>.*for
While this can technically still have results that are irrelevant to me it's already precise enough for the majority of cases.

Additional context
N/A

[lalvarezt]

Not exactly what you requested but have you tried

'impl 'traitname 'for

This makes use of the exact matching and the spaces in between act as logical ANDs