Add check for non top-level full-sentence comments

[l0kix2]

Hi, godot linter now have three options for scope

#   declarations - for top level declaration comments (default);
#   toplevel     - for top level comments;
#   all          - for all comments.

It would be nice to add one more between all and toplevel. For example (from google style guild https://google.github.io/styleguide/go/decisions#comment-sentences)

type Server struct {
    // BaseDir points to the base directory under which Shakespeare's works are stored
    baseDir string
}

doesn't trigger linter error about dot in the end of line now
Though i think it is rather normal to expect comments for struct fields to be full sentences and it would be nice to have linter validate it.