Doc: Add alt text for \image tags for qtserialbus


Alternate text (alt text) improves the documentation experience for
screen readers and for other accessibility tools.

Task-number: QTBUG-135098
Pick-to: 6.11
Change-Id: Ibdf19f376c6021d53010b713aafb9f15e4400c87
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: David Boddie <david.boddie@qt.io>
commit3e73be18b3effd46067bc326a25225fec3996492
parent5e607b61f444d92da087c69f32c2bf49a299d0b2
authorJerome Pasion <jerome.pasion@qt.io>
committerDavid Boddie <david.boddie@qt.io>
commit timeMon, 18 May 2026 10:07:11 +0000