build: distribute makekeys.py and keywords.gperf

This was an oversight: even though we ship the pre-built files, it is
still good behavior to include the original generators / source files in
the tarball.

Signed-off-by: Ran Benita <ran234@gmail.com>
doc: try to explain leds and shift levels

Remove the @todo's.

Signed-off-by: Ran Benita <ran234@gmail.com>
doc: use 'indices' instead of 'indexes' consistently

We use 'indices' in some function names so use that.

Signed-off-by: Ran Benita <ran234@gmail.com>