Add missing java.nio.file.Files methods to FileReadWrite.qll

[Marcono1234]

Adds:

• Files.lines
• Files.readString

[aschackmull]

LGTM, but could you please autoformat? Otherwise the PR check will fail.

[Marcono1234]

Sorry for the delay. Formatted the file now and force pushed (due to the low number of changed files, hope this is alright).
I also noticed that it was previously erroneously looking for a method called newInputReader instead of newInputStream, which I have fixed as well.

[aschackmull]

There is a zero-width space (U+200B) after "newInputStream, which causes PR checks to fail and would mean that the code wouldn't actually match a newInputStream call.

[Marcono1234]

Sorry for the trouble and good that you noticed it! I copied it from https://docs.oracle.com/en/java/javase/14/docs/api/index.html (to prevent any typos), but sadly the method names have this \u200B before the opening parenthesis.