chores(pop transform): standard snt init + R func docstrings

[EstebanMontandon]

Second cleaning (no functional changes)

Scripts touched:
snt_dhis2_population_transformation.ipynb

.R files touched:
snt_dhis2_population_transformation.r

additionally unnecessary try: block was removed from the python pipeline snt_dhis2_population_transformation (no functional changes)

[sPuntinG]

Also great, seems all good!

Question -- just to double check : did you also test run all edited pipelines with their associated edited .ipynb and .r files?
(as needs to be done by hand because, as we know, the pull script mechanism only pull from main not from feature branches, it's easy to forget pieces)