Option to Output Lowercase `l` Symbol for Liters

I would like to be able to switch the output of units to use a lowercase `l` for Liters.

The lowercase `l` is already supported for input (but I cannot seem to find the code for it, only a comment). I suppose I only need to define a new unit, but I would like to know the recommended way and how it would interplay with existing code for accepting `l` so that a) I don't break anything and b) my "implementation" reflects a recommended way to handle this with a view to potentially publishing my code some day.

Hence my questions:
1) Where in the code are `l` handled as input units?
2) What is the recommended way to change output units for `u"l"` from `L` to `l`?
3) Wouldn't this presumeably frequent desire make for a good example for the documentation?

#18 may be related, but that may also be in the eye of the beholder.

Thank you for your help and the very useful package.

Start by locating the input-unit handling for lowercase `l` and the existing output symbol definition for liters. Review issue #18 for related context and determine how an output preference could interact with current parsing. Done means the recommended implementation path is established, with documentation covering the lowercase-liter example.

Written by the indexing model from the issue text.