Add a CopCount formatter

[petehamilton]

Allows you to see a list of cops with offences, ordered by offence count.

e.g.

❯ be rubocop -f p -f copcount app/controllers
Inspecting 98 files
CCCCCCCCCCCCCCCWCCCCC..CCCCCC.CCCCCCCC.CCWWCCCCCC.CCCCW..CCCCCWCCCCCCCCCWCCCC.CWCCCC.CCCCCCCCWCCCC

Offences: ...SNIP...

98 files inspected, 134 offences detected

(87)  Documentation
(12)  DotPosition
(8)   AvoidGlobalVars
(7)   EmptyLines
(6)   AssignmentInCondition
(4)   Blocks
(4)   CommentAnnotation
(3)   BlockAlignment
(1)   IndentationWidth
(1)   AvoidPerlBackrefs
(1)   ColonMethodCall

[bbatsov]

Nice idea, but I have some feedback:

• The CopCount name is a bit misleading; can't think of a better name right now, though.
• You should mention the new formatter in the README
• You should fix the style problems within the code of the new formatter

@yujinakayama @jonas054 @edzhelyov Would you like to add something more?

[petehamilton]

• Agree on the name. I had the same problem, happy to go with whatever you think is best.
• Will add note to Readme.
• As for the style issues, that couldn't be more embarrassing 😉 Will fix immediately.

[bbatsov]

Looks good. Thanks!

[jonas054]

Sorry for this late reply, but I still want to comment.

• This formatter is a great idea.
• Did you consider (and reject) OffenceCount, @petehamilton ? To me it's the first thing that springs to mind. I mean it is offences, not cops, we're counting. And the letter o is not taken so it would be -f o.
• There's a bug in the formatter causing far to much space between the count and the cop name. I will add a comment to the code separately.

[jonas054]

It shouldn't be ljust(offence_count + 4). If you really want to base the justification on the total count, it should be ljust(offence_count.to_s.length + 4) or something to that effect.

[petehamilton]

Totally correct. No idea how this slipped through.

[petehamilton]

I really like OffenceCount, in fact, I had the same idea (Offences over Cops) today after rethink off @bbatsov's comments and was in the process of renaming anyway!

[bbatsov]

Well, the new version is still not out, so feel free to rename the formatter and address the rest of @jonas054's comments in a separate PR.