In several languages (PHP, Javascript, HTML, XML, ...) it's possible to use both single and double quotes for string literals (attributes in the case of HTML/XML).

So it would be nice to have a formatting option to set the desired quoting style. Currently I'm working on a project where quoting is inconsistent & this feature would allow me to simply format the whole project to make all quoting consistent.

Ideally, there would also be an option to specify what to do in case the string literal contains the desired quotes:
* leave it as is, so that there's no need to escape
* force the quoting style & escape embedded quotes
There could also be a "Threshold" option to decide when to choose what. For example: if the treshold = 3, this would mean: if there are less than 3 quotes that would need escaping, force the quoting style & escape as necessary. Else if there are at least 3 such quotes, leave it as is so as to avoid having to escape all the quotes.