cmd/go/internal/load: fix IsMetaPackage function name in doc
cmd/go/internal/load: fix IsMetaPackage function name in doc

The IsMetaPackage function was made exported when it was moved from
cmd/go to cmd/go/internal/load in CL 36196. Its documentation wasn't
updated accordingly. This change fixes that, resolving a golint issue.

Updates #18653.

Change-Id: Icf89461000754d0f09e6617b11c838e4c050d5a6
Reviewed-on: https://go-review.googlesource.com/59430
Reviewed-by: Dave Cheney <bfcdf3e6ca6cef45543bfbb57509c92aec9a39fb@cheney.net>

codestation/go,akutz/go,polyverse-security/go,josharian/go,golang/go,nawawi/go,nawawi/go,josharian/go,CAFxX/go,Cofyc/go,codestation/go,CAFxX/go,cloudflare/go,Cofyc/go,golang/go,Cofyc/go,codestation/go,Cofyc/go,codestation/go,akutz/go,golang/go,nawawi/go,codestation/go,josharian/go,akutz/go,nawawi/go,cloudflare/go,polyverse-security/go,josharian/go,akutz/go,cloudflare/go,akutz/go,CAFxX/go,codestation/go,cloudflare/go,golang/go,codestation/go,akutz/go,nawawi/go,nawawi/go,polyverse-security/go,polyverse-security/go,christopher-henderson/Go,cloudflare/go,josharian/go,josharian/go,josharian/go,Cofyc/go,golang/go,polyverse-security/go,akutz/go,polyverse-security/go,golang/go,CAFxX/go,Cofyc/go,cloudflare/go,nawawi/go,josharian/go,Cofyc/go,akutz/go,cloudflare/go,CAFxX/go,codestation/go,polyverse-security/go,polyverse-security/go,CAFxX/go,Cofyc/go,CAFxX/go,golang/go,nawawi/go,golang/go,cloudflare/go,CAFxX/go