Add Giscus widget to documentation #1377

Job	Run time
sdist	55s
ruff	9s
mypy	29s
parse_sdl (macos-latest, 3.2.16)	29s
parse_sdl (windows-latest, 3.2.16)	44s
pyodide	2m 55s
build-macos (pp310-*)	3m 51s
build-macos (cp310-*_universal2)	1m 59s
test-docs	1m 49s
linux-wheels (x86_64, pp310-manylinux*)	4m 8s
linux-wheels (x86_64, cp310-manylinux*)	4m 41s
tox (ubuntu-latest)	2m 7s
linux-wheels (aarch64, cp310-manylinux*)	4m 7s
linux-wheels (aarch64, pp310-manylinux*)	3m 34s
build (ubuntu-latest, pypy-3.10, x64)	3m 0s
build (windows-11-arm, 3.11, arm64)	3m 57s
build (windows-latest, 3.10, x86)	3m 43s
build (ubuntu-latest, 3.10, x64)	3m 55s
build (windows-latest, pypy-3.10, x64)	4m 32s
build (windows-latest, 3.10, x64)	2m 47s
publish	0s
	53m 51s

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