Quickly create reStructuredText overlines (and underlines) in Vim§

I format H1-level section titles in reStructuredText with an overline and underline, like this:

=============
Hello, world!
=============

The sequence of = characters above Hello, world! is the overline, and the sequence below is the underline.

To quickly create overlines and underlines in Vim:

Write the H1-level section title text.
```
Hello, world!
```
Yank the line with yy and then duplicate it with p.
```
Hello, world!
Hello, world!
```
Press Vr= to create the underline.
```
Hello, world!
=============
```
Yank the underline with yy then press kk to move up 2 lines then p to paste.
```
=============
Hello, world!
=============
```