qga/qapi-schema: Reformat doc comments to conform to current conventions

Change

    # @name: Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed
    #        do eiusmod tempor incididunt ut labore et dolore magna aliqua.

to

    # @name: Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed
    #     do eiusmod tempor incididunt ut labore et dolore magna aliqua.

See recent commit "qapi: Relax doc string @name: description
indentation rules" for rationale.

Reflow paragraphs to 70 columns width, and consistently use two spaces
to separate sentences.

To check the generated documentation does not change, I compared the
generated HTML before and after this commit with "wdiff -3".  Finds no
differences.  Comparing with diff is not useful, as the reflown
paragraphs are visible there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230428105429.1687850-17-armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>