Add CSV output format to crystal tool unreachable

[straight-shoota]

The CSV format makes it easy to use the output for data analysis.

Example output:

name,file,line,column,length,annotations
top-level foo,.test/foobar.cr,1,1,3,
top-level foo,.test/foobar.cr,7,1,3,"@[Deprecated(""You should use `bar`"")] @[Experimental]"
top-level bar,.test/foobar.cr,13,1,3,"@[Deprecated(""You should use `foo`\nreally!"")]"
Foo#foo,.test/foobar.cr,24,3,2,
Foo.foo,.test/foobar.cr,30,3,2,
top-level foo_yield,.test/foobar.cr,40,1,3,
top-level foo_proc,.test/foobar.cr,50,1,3,
"FooG(G, H)#foo",.test/foobar.cr,69,3,2,