CONTRIBUTING.md does not mention format of top comment

[JHaig343]

the part in particular:

# Tests
A test file is required with language additions. The file should
contain every variant comments and quotes, as well as a comment
at the top of the file containing the manually verified lines,
code, comments, blanks e.g.
`// 39 lines 32 code 2 comments 5 blanks`. The comment should use
the syntax of the language you're testing. A good example of a
test file is [`tests/data/rust.rs`].

Currently for tests to successfully run, the top comment needs to have a specific format:
X lines X code X comments X blanks
Which to md file does not mention. I propose adding to the md file to specifically mention the required format of the top comment.

[JHaig343]

#63

[XAMPPRocky]

Thank you for your issue! I've updated the contributing information.