Clean up output

[schneems]

I previously left a comment stating I didn't know why a certain method existed. In investigating the code in CaptureCodeContext#capture_before_after_kws I found that it was added as to give a slightly less noisy output.

The docs for AroundBlockScan#capture_neighbor_context only describe keywords as being a primary concern. I modified that code to only include lines that are keywords or ends. This reduces the output noise even more.

This allows me to remove that start_at_next_line method.

One weird side effect of the prior logic is it would cause this code to produce this output:

        class OH
          def hello

          def hai
          end
        end

          1  class OH
        > 2    def hello
          4    def hai
          5    end
          6  end

But this code to produce this output:

        class OH
          def hello
          def hai
          end
        end

          1  class OH
        > 2    def hello
          4    end
          5  end

Note the missing def hai. The only difference between them is that space.

With this change, they're now both consistent.