Add blockquote to MessageEntityType #723

Job	Run time
rustfmt	15s
Test stable ubuntu-latest --no-default-features	1m 31s
Test stable ubuntu-latest	1m 52s
Test stable ubuntu-latest --all-features	2m 4s
Test stable macos-latest --no-default-features	4m 36s
Test stable macos-latest	3m 1s
Test stable macos-latest --all-features	3m 34s
Test stable windows-latest --no-default-features	3m 58s
Test stable windows-latest	4m 27s
Test stable windows-latest --all-features	5m 1s
Test beta ubuntu-latest --all-features	2m 1s
Test nightly ubuntu-latest --all-features	1m 59s
Release x86_64-unknown-linux-gnu	1m 5s
Release aarch64-unknown-linux-gnu	1m 7s
Release armv7-unknown-linux-gnueabihf	1m 9s
Release arm-unknown-linux-gnueabihf	1m 14s
Release riscv64gc-unknown-linux-gnu	1m 8s
Release x86_64-apple-darwin	1m 20s
Release aarch64-apple-darwin	1m 22s
Release x86_64-pc-windows-msvc	2m 8s
Release aarch64-pc-windows-msvc	3m 11s
	48m 3s

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