Fixed docstring of return value of the srloop and srploop functions

[ronymunitz]

Fixed return value of the srloop and srploop functions. The return value was updated in the comment, but not in the docstring.

[guedou]

Thanks for this PR!

[codecov]

Codecov Report

Merging #4060 (32ec515) into master (6dbdc37) will increase coverage by 0.00%.
Report is 199 commits behind head on master.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4060   +/-   ##
=======================================
  Coverage   81.95%   81.95%           
=======================================
  Files         327      327           
  Lines       75540    75554   +14     
=======================================
+ Hits        61911    61923   +12     
- Misses      13629    13631    +2     

Files	Coverage Δ
scapy/sendrecv.py	87.95% <ø> (-0.16%)	⬇️

... and 10 files with indirect coverage changes

[polybassa]

Retrigger tests

[ronymunitz]

Added another fix in the docstring, regarding the AsyncSniffer/sniff docstring.

[gpotter2]

So I doubt this is very useful. This is basically only ever shown in help(), in which case I would much rather have a user friendly typing. Generally, the current docstrings is also very unhelpful so I believe it would be better to simply redo it using words, and sphinx :param: tags.