Fixed some minor spelling mistakes

Having that implementation in the tree even though it was superceded is
confusing and really unnecessary.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

This patch addes a "LICENSE" file, explaining our copyright status and
3-clause BSD license.

It also includes in documentation/LICENSE-* the licenses of the four projects
we copied code from - FreeBSD, Prex, Open Solaris and Musl. Our top-level
LICENSE file refers to these separate LICENSE files.

allows commands to specify a delimiter between tab completion
suggestions, the default is '\t' in case this function is not present
in the command interface.

the tab_pretty(arg) function is called just before printing an
autocompleted suggestion, it may be used by commands to prettify their
autocompletion output, will shortly be used by the cd command