Please add the new feature to documentation

[Radoom]

First of all: !!! Thanks for your awesome work !!!

@
re PR: arendst/tasmota#

In Tasmota documentation / SmartMeter Interface
for Device ZPA GH305 (SML), please add a hint to the (maybe) required PIN to unlock this Device.
"Energy provider may have to supply a PIN code to enable output of additional data."

For this device a "PIN" may be required, which can be obtained from the grid provider / meter operator ("Messstellenbetreiber").
See here for example cases where this was necessary: arendst/Tasmota#18091

Will likely save others from some searching around if they directly get this hint.

[mi-hol]

@Radoom to reflect what is desired, please change issue Title to "for Device ZPA GH305 (SML), add a hint for required PIN"