docs: remove additional unnecessary files

Many of the generated files in the docs site are not strictly necessary
for our usage; pare down to the minimum for distribution.

Makefile

@@ -50,7 +50,7 @@ mandocs: $(mandocs)
 htmldocs:
 	cd docs && node ../bin/npm-cli.js install --legacy-peer-deps --no-audit && \
 	node ../bin/npm-cli.js run build:static >&2 && \
-	rm -rf node_modules .cache public/*js public/*json public/404* public/page-data public/manifest*
+	rm -rf .cache public/*js public/*json public/404* public/page-data public/manifest* public/*.map public/*.LICENSE.txt public/static
 
 docs: mandocs htmldocs