bug#33664: 26.1; Document vars and functions in `cursor-sensor.el'

[Drew Adams <drew.adams@oracle.com>]

Please document the variables and functions in `cursor-sensor.el'.  It
would be a step backward for Emacs to document less and less.  Calling
something an "internal" function is not, in itself, a sufficient reason
not to give it a doc string.

In particular, please add a doc string for variable
`cursor-sensor-inhibit'.

I was reading the `isearch.el' code and saw this: (push 'isearch
cursor-sensor-inhibit).  Had to start searching `cursor-sensor.el' to
try to understand what this variable is for.  Even that didn't really
help, since there is nothing in `cursor-sensor.el' that would lead one
to understand that the variable is used somehow as a list of values.

Even grepping for that var didn't help with such understanding, as there
are no uses of it outside of isearch.el.

Isearch apparently goes to the trouble of allowing for the var to be
used as a list (similar to `buffer-invisibility-spec', perhaps), but
there is no comment, doc, or spec describing this behavior/use in
`cursor-sensor.el'.


In GNU Emacs 26.1 (build 1, x86_64-w64-mingw32)
 of 2018-05-30
Repository revision: 07f8f9bc5a51f5aa94eb099f3e15fbe0c20ea1ea
Windowing system distributor `Microsoft Corp.', version 10.0.16299
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''