re.findall(r"\w+ly", text) does not find all adverbs in a sentence, it finds words that contain ly (not ending with ly) :
if text= 'andlying clearly', output: [andly, clearly]
which is wrong! 
the right way to do this is re.findall(r'\b(\w+ly)\b',text)
output= clearly!

Please submit a PR.

The parenthesis are not needed:
   re.findall(r"\b\w+ly\b", text)

re.findall(r"\w+ly", text) does not find all adverbs in a sentence, it finds words that contain ly (not ending with ly) :
if text= 'andlying clearly', output: [andly, clearly]
which is wrong! 
the right way to do this is re.findall(r'\b\w+ly\b',text)
output= clearly!

While I don't want to start a philosical discussion -- is that really better? Finding adverbs with a regex doesn't work in the general case -- think butterfly, panoply, well -- and the example is meant to illustrate the usage of re.findall() rather than regex syntax.

"finding adverbs" is just shorter and easier to understand than "finding sequences of word characters that end with "ly".

I think it's fine as-is.  The real purpose of the example is show basic patterns in writing regexes.  Pig-latin examples or searching for words ending in -ly make for nice beginner examples.   I like the OP's modification because it teaches a general skill (the importance of \b for making sure you get whole words).

We could add a link to the Natural Language Toolkit for people who are getting serious about searching for parts of speech.

fixed finding adverbs example in re docs