plugins/go: Simplify/fix recursive golang format (#7027)

Per the [`go` command specification](https://golang.org/cmd/go/#hdr-Package_lists),
the `...` wildcard matches the empty string. This makes commands like
`go <action> . ./...` unnecessary: they should use `go <action> ./...`.

This also fixes a bug with the `gofa` shortcut, where it would emit an
error if called from a directory containing no go source files (but
having subdirectories that _did_ contain go files).

plugins/golang/golang.plugin.zsh

@@ -184,7 +184,7 @@ alias gob='go build'
 alias goc='go clean'
 alias god='go doc'
 alias gof='go fmt'
-alias gofa='go fmt . ./...'
+alias gofa='go fmt ./...'
 alias gog='go get'
 alias goi='go install'
 alias gol='go list'