Remove suggestion to underscore internal function paramaters #79
Description
The convention to add an underscore to the parameter names of internal function was removed in vyper in vyperlang/vyper#2166
Thus, this no longer applies and we should remove this statement in https://github.com/vyperfun/vyper.fun/blob/master/1/external_internal_functions.md .
Note that this does not affect internal function names, only their parameter names.
At the time of writing this however, due to a bug in vyper this still fails for function arguments, although it is fine for local variable names.