spec: fix examples for predeclared function complex
spec: fix examples for predeclared function complex

Fixes #17398.

Change-Id: Iac7899031c1bfbadc4f84e5b374eaf1f01dff8c8
Reviewed-on: https://go-review.googlesource.com/31190
Reviewed-by: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>
Reviewed-by: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>

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