chore: tidy up c binding build and docs #7838

Job	Run time
build-c-doc	27s
build-cpp-doc	27s
build-dav-server-opendalfs-doc	53s
build-fuse3-opendal-doc	55s
build-haskell-doc	3m 19s
build-java-doc	14s
build-lua-doc	11s
build-nodejs-doc	20s
build-object-store-opendal-doc	55s
build-ocaml-doc	4m 38s
build-opendal-compat-doc	42s
build-parquet-opendal-doc	54s
build-python-doc	3m 7s
build-rust-doc	4m 49s
build-unftp-sbe-opendal-doc	1m 22s
build-virtiofs-opendal-doc	53s
build-website	2m 20s
	26m 26s

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