shell: improve partial completion
shell: improve partial completion

Shell used to require adding commands and subcommands in alphabetical
order to ensure correct autocompletion and printing options with the
<Tab> key.

Commit: bd3a4e5fe581a0f1903f1b6838e3a3308d03fc35 implemented correct
options printing with the <Tab> key for not sorted commands.
This PR allows to partially autocomplete not sorted commands.

Signed-off-by: Jakub Rzeszutko <db01fea5b4491dba4fc272e7096cf665c7b907b9@nordicsemi.no>

zephyrproject-rtos/zephyr,galak/zephyr,explora26/zephyr,explora26/zephyr,punitvara/zephyr,nashif/zephyr,galak/zephyr,punitvara/zephyr,finikorg/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,punitvara/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,explora26/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,finikorg/zephyr,ldts/zephyr,ldts/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,Vudentz/zephyr,punitvara/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,punitvara/zephyr,galak/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,nashif/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,ldts/zephyr,galak/zephyr,explora26/zephyr,finikorg/zephyr,ldts/zephyr