patch 8.2.4538: the find_tags_in_file() function is too long

Problem:    The find_tags_in_file() function is too long.
Solution:   Refactor into smaller functions. (Yegappan Lakshmanan,
            closes #9920)
diff --git a/src/version.c b/src/version.c
index 6aa798f..48f2f01 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4538,
+/**/
     4537,
 /**/
     4536,