[explicit-imports-plugin] sort imported symbols

## Is your enhancement request related to a problem? Please describe.

It seems as of HLS 2.13 the hls-explicit-imports-plugin does not order the explicit imports for a module lexically.
(Not sure how they are getting ordered, perhaps just by usage order?)

eg It suggested:

`import Data.List.Extra ( singleton, dropPrefix, nubSort, splitOn )`

instead of

`import Data.List.Extra (dropPrefix, nubSort, singleton, splitOn)`

## Describe the solution you'd like

It would be nice to sort the explicitly imported functions, etc

## Additional context

I glanced at the code, but it was a bit above my head: perhaps I would need to understand text ranges etc