fix typos #258

Job	Run time
Intra-doc links	1m 21s
Build target wasm32-unknown-unknown	1m 41s
Book tests	1m 20s
Build target wasm32-wasi	1m 33s
Bitrot check	1m 38s
Rustfmt	14s
Test on ubuntu-latest	7m 11s
Test on i686-unknown-linux-gnu	13m 22s
Test on windows-latest	10m 37s
Test on i686-unknown-linux-gnu with beta features	13m 13s
Test on macOS-latest	6m 50s
Test on i686-unknown-linux-gnu with nightly features	15m 5s
Test on ubuntu-latest with beta features	7m 4s
Test on windows-latest with beta features	10m 48s
Test on macOS-latest with beta features	8m 46s
Test on ubuntu-latest with nightly features	8m 8s
Test on windows-latest with nightly features	11m 11s
Test on macOS-latest with nightly features	11m 29s
	2h 11m 31s

Provide feedback