Add deduplicate to strings

[jasonmccreary]

This adds a convenience method to replace consecutive occurrences of a character with character. Or, more commonly, deduplicate characters within a string.

Str::dedup('random  double  spaces'); // 'random double spaces'
Str::dedup('/some//odd/path//', '/'); // '/some/odd/path/'
Str::dedup('zondaaaa', 'a');          // 'zonda'

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Note: While a second parameter might have been added to squish, their primary intention felt different. squish also exists in other languages. So creating a separate, new method seemed more appropriate than expanding the squish behavior within Laravel.

[timopaul]

@jasonmccreary, I think there is a lot more power in the method if the second parameter could also be an array of characters or a string from which all characters are handled separately. What do you think?

[jasonmccreary]

Yeah, that's interesting, kind of like trim. I'd almost opt for an array though to avoid any confusion that you could pass in a string to dedup. Then again, you can now... So that'd be a change of behavior.

I think best to leave it alone for now.