accessibility: speakup: phonetic spelling while arrowing letter by letter

accessibility: speakup: phonetic spelling while arrowing letter by letter

This patch includes an enhancement requested frequently on the mailing
list.[1][2] It adds a variable, cur_phonetic in the spk_vars, which can
be set as a module parameter, as well as in /sys/speakup/cur_phonetic.
This patch also documents cur_phonetic as a sysfs attribute in
sysfs-driver-speakup.

When cur_phonetic=1, it causes speakup to speak letters phonetically if
paused on the character while arrowing through a word.

When a user does not set cur_phonetic to any value, the default value
for it would be 0.

[1]: https://github.com/linux-speakup/speakup/issues/6
[2]: https://github.com/linux-speakup/speakup/issues/5

since V1:
	- removed unnecessary lines

Signed-off-by: Mushahid Hussain<mushi.shar@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Link: https://lore.kernel.org/r/20221115100530.91174-3-mushi.shar@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>