parsers: warn about unknown input/output module option keys

parsers: warn about unknown input/output module option keys

Misspelled option names fail silently, the setting won't take effect and
the user won't notice.

  $ echo "1, 0" | sigrok-cli -I csv:header=no:column_format=t,l -i -

Check whether specified input/output module options are supported, emit
warnings when they are not. It's a design choice to raise awareness yet
make mismatches non-fatal. This can be useful for generated command lines
or during a period of migration after UI changes.

The implementation is prepared for optional call site specific captions in
diagnostics messages. Callers can either have messages generated by common
code, or handle the list of unavailable words themselves, or have common
code emit warnings and in addition take extra actions. It's also trivial
to make mismatches fatal should the need arise.

This resolves the sigrok-cli part of bug #1549. Also addresses brace style
nits in bypassing.