patch 8.2.2871: unnessary VIM_ISDIGIT() calls, badly indented code

Problem:    Unnessary VIM_ISDIGIT() calls, badly indented code.
Solution:   Call skipdigits() on the next character.  Improve indenting.
            (Dominique Pellé, closes #8227)
diff --git a/src/ops.c b/src/ops.c
index d8e96ff..e4590a1 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -3985,12 +3985,13 @@
 		op_formatexpr(oap);	// use expression
 	    else
 #endif
+	    {
 		if (*p_fp != NUL || *curbuf->b_p_fp != NUL)
-		op_colon(oap);		// use external command
-	    else
-		op_format(oap, FALSE);	// use internal function
+		    op_colon(oap);		// use external command
+		else
+		    op_format(oap, FALSE);	// use internal function
+	    }
 	    break;
-
 	case OP_FORMAT2:
 	    op_format(oap, TRUE);	// use internal function
 	    break;