docs/devel: move API to end of tcg-plugins.rst

The API documentation is quite dry and doesn't flow nicely with the
rest of the document. Move it to its own section at the bottom along
with a little leader text to remind people to update it.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220929114231.583801-39-alex.bennee@linaro.org>
1 file changed