doc: Fix some typos on the Kconfig best practices page
doc: Fix some typos on the Kconfig best practices page

Found some copy-paste errors while going through it.

Signed-off-by: Ulf Magnusson <01743f1c1deb1fe75271d62edb65757d98ac0bcb@nordicsemi.no>

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