I don't know any plugins that do it. I know you can do it very easily by using a regex search:
Menu > Find > Find in files...
Then turn on regular expression search (regex) and use the following values:
Remember to NOT click on the Replace button, as it removes all lines.
Then press search. If you scroll to the bottom, you get something like "30036 matches across 282 files" That means, 30036 lines in 282 code files.