patch 8.2.4473: Coverity warnds for not checking return value of ftell()

Problem:    Coverity warnds for not checking return value of ftell().
Solution:   Bail out if ftell() returns a negative value.

src/spellfile.c

@@ -6256,6 +6256,8 @@ spell_add_word(
 	    {
 		fpos = fpos_next;
 		fpos_next = ftell(fd);
+		if (fpos_next < 0)
+		    break;  // should never happen
 		if (STRNCMP(word, line, len) == 0
 			&& (line[len] == '/' || line[len] < ' '))
 		{

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4473,
 /**/
     4472,
 /**/