feature request: let the colour for colored-completion-prefix try some custom field in LS_COLORS first

[Christoph Anton Mitterer]

Hey.

AFAIU, the colour for the common prefix in colored-completion-prefix is
coming right now from the "so" field, that is sockets, of LS_COLORS.


Seems to be done by the:
#define C_PREFIX        C_SOCK
in colors.h.


It would be nice readline tries a dedicated field first and only if
that is not set, fall back to "so".

Since LS_COLORS seems to allow adding any '*.extension=' fields, one
could use one of these, without any compatibility issues.

e.g. LS_COLORS='...:*.readline-colored-completion-prefix=02:...'



What would be even nicer was, but probably harder to implement if one
could set a escape sequence that's combined with the colour that would
result from colored-stats.

The idea is kinda, that if e.g. multiple files are printed, one can set
that the common prefix uses the dim colour version of whichever colour
the current file would have.
Or instead of dim, underlined, bold, blinking, whatsoever.


This would make the output a little bit less over-coloured, but one
could still see the common prefix.



Thanks,
Chris.