doc/go1.14: change hash/maphash package link
doc/go1.14: change hash/maphash package link

Package name and documentation link were wrong.

Change-Id: I274906afc3cf7a3d88e3da76549cd6ab008fd0c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/212538
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

akutz/go,CAFxX/go,cloudflare/go,nawawi/go,cloudflare/go,golang/go,golang/go,CAFxX/go,cloudflare/go,CAFxX/go,cloudflare/go,CAFxX/go,nawawi/go,cloudflare/go,golang/go,golang/go,nawawi/go,akutz/go,golang/go,CAFxX/go,cloudflare/go,golang/go,nawawi/go,CAFxX/go,nawawi/go,CAFxX/go,akutz/go,nawawi/go,akutz/go,CAFxX/go,golang/go,nawawi/go,akutz/go,akutz/go,golang/go,akutz/go,nawawi/go,cloudflare/go,akutz/go,cloudflare/go