doc: Supplement list of implemented socket operations
doc: Supplement list of implemented socket operations

Add sendto() and recvfrom() to the list of implemented operations
in BSD Socket API.

Signed-off-by: Stig Bjørlykke <ea07fa156e332ba20900aa10589adbee8ec38deb@nordicsemi.no>

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