Sort reference line numbers as numbers

[Ortham]

So that "source-file.js:20" appears before "source-file.js:100". Also sort references line by line, so that e.g.

path.js:122 path.js:98

is now written as

path.js:98 path.js:122

and sorted after path.js:90 and before path.js:100.

For a real-life example of how this change looks, see this commit diff.