patch 9.1.1428: completion: register completion needs cleanup

Problem:  completion: register completion needs cleanup
Solution: slightly refactor get_register_completion()
          (glepnir)

closes: #17432

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/insexpand.c b/src/insexpand.c
index 9b5eec5..7ecac6e 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -4905,11 +4905,11 @@
     int		dir = compl_direction;
     yankreg_T	*reg = NULL;
     void	*reg_ptr = NULL;
+    int		adding_mode = compl_status_adding();
 
     for (int i = 0; i < NUM_REGISTERS; i++)
     {
 	int regname = 0;
-
 	if (i == 0)
 	    regname = '"';    // unnamed register
 	else if (i < 10)
@@ -4935,14 +4935,14 @@
 
 	reg = (yankreg_T *)reg_ptr;
 
-	if (compl_status_adding())
+	for (int j = 0; j < reg->y_size; j++)
 	{
-	    for (int j = 0; j < reg->y_size; j++)
-	    {
-		char_u *str = reg->y_array[j].string;
-		if (str == NULL)
-		    continue;
+	    char_u *str = reg->y_array[j].string;
+	    if (str == NULL)
+		continue;
 
+	    if (adding_mode)
+	    {
 		int str_len = (int)STRLEN(str);
 		if (str_len == 0)
 		    continue;
@@ -4953,19 +4953,13 @@
 				: STRNCMP(str, compl_orig_text.string,
 					    compl_orig_text.length) == 0))
 		{
-		    if (ins_compl_add_infercase(str, str_len, p_ic, NULL, dir, FALSE, 0) == OK)
+		    if (ins_compl_add_infercase(str, str_len, p_ic, NULL,
+							dir, FALSE, 0) == OK)
 			dir = FORWARD;
 		}
 	    }
-	}
-	else
-	{
-	    for (int j = 0; j < reg->y_size; j++)
+	    else
 	    {
-		char_u *str = reg->y_array[j].string;
-		if (str == NULL)
-		    continue;
-
 		// Calculate the safe end of string to avoid null byte issues
 		char_u *str_end = str + STRLEN(str);
 		char_u *p = str;
diff --git a/src/version.c b/src/version.c
index c9a1c16..7c3c4f1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -710,6 +710,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1428,
+/**/
     1427,
 /**/
     1426,