Sort output by file line order rather than rule number

[JayBeeDe]

Describe the Enhancement:

Add a CLI parameter such as "-S" flag in order to require the output to be sorted by file line number rather than line reference.

Impacted Rules:

All rules

Describe the Need:

Current implementation example

mdl README.md -r "~MD033,~MD013"
README.md:6: MD004 Unordered list style
README.md:7: MD004 Unordered list style
README.md:10: MD004 Unordered list style
README.md:11: MD004 Unordered list style
README.md:12: MD004 Unordered list style
README.md:13: MD004 Unordered list style
README.md:161: MD004 Unordered list style
README.md:162: MD004 Unordered list style
README.md:175: MD004 Unordered list style
README.md:176: MD004 Unordered list style
README.md:177: MD004 Unordered list style
README.md:179: MD004 Unordered list style
README.md:62: MD029 Ordered list item prefix
README.md:71: MD029 Ordered list item prefix
README.md:74: MD029 Ordered list item prefix
README.md:77: MD029 Ordered list item prefix
README.md:80: MD029 Ordered list item prefix
README.md:71: MD032 Lists should be surrounded by blank lines
README.md:74: MD032 Lists should be surrounded by blank lines
README.md:77: MD032 Lists should be surrounded by blank lines
README.md:80: MD032 Lists should be surrounded by blank lines

A detailed description of the rules is available at https://github.com/markdownlint/markdownlint/blob/master/docs/RULES.md

Target implementation example

mdl README.md -r "~MD033,~MD013" -S
README.md:6: MD004 Unordered list style
README.md:7: MD004 Unordered list style
README.md:10: MD004 Unordered list style
README.md:11: MD004 Unordered list style
README.md:12: MD004 Unordered list style
README.md:13: MD004 Unordered list style
README.md:62: MD029 Ordered list item prefix
README.md:71: MD029 Ordered list item prefix
README.md:71: MD032 Lists should be surrounded by blank lines
README.md:74: MD029 Ordered list item prefix
README.md:74: MD032 Lists should be surrounded by blank lines
README.md:77: MD029 Ordered list item prefix
README.md:77: MD032 Lists should be surrounded by blank lines
README.md:80: MD029 Ordered list item prefix
README.md:80: MD032 Lists should be surrounded by blank lines
README.md:161: MD004 Unordered list style
README.md:162: MD004 Unordered list style
README.md:175: MD004 Unordered list style
README.md:176: MD004 Unordered list style
README.md:177: MD004 Unordered list style
README.md:179: MD004 Unordered list style

A detailed description of the rules is available at https://github.com/markdownlint/markdownlint/blob/master/docs/RULES.md

Current Alternative

Using the bash sort function:

mdl README.md -r "~MD033,~MD013" | sort -V

[jaymzh]

Seems reasonable. I'd accept a PR for that.