Grammar: remove hyphens from predicate adjective “up to date” (#9356)

https://english.stackexchange.com/a/180617
https://web.archive.org/web/20190728053012id_/grammarist.com/usage/up-to-date/#text-60

plugins/golang/golang.plugin.zsh

@@ -41,7 +41,7 @@ __go_tool_complete() {
     return
   fi
   build_flags=(
-    '-a[force reinstallation of packages that are already up-to-date]'
+    '-a[force reinstallation of packages that are already up to date]'
     '-n[print the commands but do not run them]'
     '-p[number of parallel builds]:number'
     '-race[enable data race detection]'