docs/devel: be consistent about example plugin names

Some plugins were prefixed with `.c`, some were not. Since the name is
essentially the full-name of the plugin file, it's logical to include
the extension.

Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
Message-Id: <20210830121534.656559-1-ma.mandourr@gmail.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
1 file changed