docs/devel/qapi-code-gen: Clean up use of quotes a bit

Section "Definition documentation" uses both single and double quotes
around doc text snippets.  Stick to double quotes.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230428105429.1687850-2-armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
1 file changed