VIPS v8.10.1 fails to build on Debian/Sid
"Namespace conflict: DocSection('rect')" error during build.

To Reproduce
Steps to reproduce the behavior:

1. On Debian/Sid: 'apt source vips'
2. Do 'dpkg-buildpackage' in vips-8.10.1 directory.

Actual behavior
During the generation of Vips-8.0.gir:
Traceback (most recent call last):
File "/usr/bin/g-ir-scanner", line 99, in
sys.exit(scanner_main(sys.argv))
File "/usr/lib/x86_64-linux-gnu/gobject-introspection/giscanner/scannermain.py", line 606, in scanner_main
main.transform()
[...]
File "/usr/lib/x86_64-linux-gnu/gobject-introspection/giscanner/ast.py", line 461, in append
raise ValueError("Namespace conflict: %r" % (node, ))
ValueError: Namespace conflict: DocSection('rect')
make[3]: *** [/usr/share/gobject-introspection-1.0/Makefile.introspection:156: Vips-8.0.gir] Error 1

Full build log: http://qa-logs.debian.net/2020/09/26/vips_8.10.1-1_unstable.log

Environment

• OS: up to date Debian/Sid on amd64
• Vips: 8.10.1
• Python: 3.18.6
• gobject-introspection: 1.66.0