GetAnnotation extracts the annotation from comment text.

ParseDir parses the Go files under given directory and parses the annotation by invoking the parseFn function on each comment group (multi-lines comments).

ParseFile parses given filename or content src and parses annotations by invoking the parseFn function on each comment group (multi-lines comments).

ParseKV parses key-value string formatted as "foo=bar" and returns key and value.