Treat ValidArgsFunction similarly to ValidArgs

This change is to have ValidArgsFunction behave like ValidArgs
specifically for the case where a command has ValidArgsFunction and also
has sub-commands.  To mimic ValidArgs, ValidArgsFunction will take
precedence over sub-commands during completion.

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

bash_completions.go

@@ -182,6 +182,10 @@ __%[1]s_handle_reply()
     completions=("${commands[@]}")
     if [[ ${#must_have_one_noun[@]} -ne 0 ]]; then
         completions=("${must_have_one_noun[@]}")
+    elif [[ -n "${has_completion_function}" ]]; then
+        # if a go completion function is provided, defer to that function
+        completions=()
+        __%[1]s_handle_go_custom_completion
     fi
     if [[ ${#must_have_one_flag[@]} -ne 0 ]]; then
         completions+=("${must_have_one_flag[@]}")
@@ -197,18 +201,13 @@ __%[1]s_handle_reply()
     fi
 
     if [[ ${#COMPREPLY[@]} -eq 0 ]]; then
-        # if a go completion function is provided, defer to that function
-        if [ -n "${has_completion_function}" ]; then
-            __%[1]s_handle_go_custom_completion
-        else
-            if declare -F __%[1]s_custom_func >/dev/null; then
-                # try command name qualified custom func
-                __%[1]s_custom_func
-            else
-                # otherwise fall back to unqualified for compatibility
-                declare -F __custom_func >/dev/null && __custom_func
-            fi
-        fi
+		if declare -F __%[1]s_custom_func >/dev/null; then
+			# try command name qualified custom func
+			__%[1]s_custom_func
+		else
+			# otherwise fall back to unqualified for compatibility
+			declare -F __custom_func >/dev/null && __custom_func
+		fi
     fi
 
     # available in bash-completion >= 2, not always present on macOS