Add Giscus widget to documentation #1378

Job	Run time
mypy	22s
sdist	59s
ruff	8s
parse_sdl (windows-latest, 3.2.16)	55s
parse_sdl (macos-latest, 3.2.16)	33s
pyodide	2m 37s
test-docs	2m 0s
tox (ubuntu-latest)	2m 22s
build-macos (pp310-*)	5m 3s
build-macos (cp310-*_universal2)	2m 35s
linux-wheels (x86_64, pp310-manylinux*)	3m 39s
linux-wheels (x86_64, cp310-manylinux*)	4m 32s
linux-wheels (aarch64, cp310-manylinux*)	4m 3s
linux-wheels (aarch64, pp310-manylinux*)	3m 27s
build (ubuntu-latest, pypy-3.10, x64)	2m 57s
build (windows-latest, 3.10, x64)	2m 50s
build (windows-latest, 3.10, x86)	6m 46s
build (ubuntu-latest, 3.10, x64)	3m 38s
build (windows-11-arm, 3.11, arm64)	3m 59s
build (windows-latest, pypy-3.10, x64)	4m 36s
publish	0s
	58m 1s

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