encoding/binary: document the new bool support
encoding/binary: document the new bool support

Updates #16856

Change-Id: I57af6b0c0d5ecdaf19cf6f969b05ec9ec03058f1
Reviewed-on: https://go-review.googlesource.com/33756
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

cloudflare/go,vsekhar/elastic-go,polyverse-security/go,polyverse-security/go,polyverse-security/go,cloudflare/go,Cofyc/go,josharian/go,nawawi/go,vsekhar/elastic-go,derekmarcotte/go,cloudflare/go,vsekhar/elastic-go,suncycheng/go,linux-on-ibm-z/go,CAFxX/go,linux-on-ibm-z/go,CAFxX/go,josharian/go,cloudflare/go,linux-on-ibm-z/go,golang/go,linux-on-ibm-z/go,derekmarcotte/go,polyverse-security/go,CAFxX/go,akutz/go,suncycheng/go,cloudflare/go,josharian/go,ImJasonH/go,josharian/go,codestation/go,goodlang/good,codestation/go,nawawi/go,Cofyc/go,CAFxX/go,derekmarcotte/go,codestation/go,christopher-henderson/Go,ImJasonH/go,nawawi/go,linux-on-ibm-z/go,ImJasonH/go,josharian/go,akutz/go,ImJasonH/go,ImJasonH/go,vsekhar/elastic-go,goodlang/good,goodlang/good,Cofyc/go,josharian/go,josharian/go,nawawi/go,derekmarcotte/go,goodlang/good,golang/go,polyverse-security/go,suncycheng/go,vsekhar/elastic-go,nawawi/go,codestation/go,nawawi/go,CAFxX/go,codestation/go,cloudflare/go,linux-on-ibm-z/go,akutz/go,Cofyc/go,cloudflare/go,goodlang/good,cloudflare/go,suncycheng/go,nawawi/go,linux-on-ibm-z/go,golang/go,golang/go,polyverse-security/go,suncycheng/go,suncycheng/go,suncycheng/go,nawawi/go,vsekhar/elastic-go,ImJasonH/go,Cofyc/go,ImJasonH/go,akutz/go,polyverse-security/go,derekmarcotte/go,goodlang/good,codestation/go,suncycheng/go,codestation/go,Cofyc/go,codestation/go,golang/go,vsekhar/elastic-go,akutz/go,Cofyc/go,CAFxX/go,golang/go,ImJasonH/go,josharian/go,vsekhar/elastic-go,akutz/go,linux-on-ibm-z/go,golang/go,derekmarcotte/go,CAFxX/go,goodlang/good,akutz/go,goodlang/good,CAFxX/go,polyverse-security/go,derekmarcotte/go,derekmarcotte/go,Cofyc/go,akutz/go,golang/go