spec: update language on type switches to match implementations
spec: update language on type switches to match implementations

See the issue below for details.

Fixes #16794.

Change-Id: I7e338089fd80ddcb634fa80bfc658dee2772361c
Reviewed-on: https://go-review.googlesource.com/27356
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

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