patch 8.1.0270: checking for a Tab in a line could be faster

Problem:    Checking for a Tab in a line could be faster.
Solution:   Use strchr() instead of strrchr(). (closes #3312)
diff --git a/src/version.c b/src/version.c
index da43f60..d92e778 100644
--- a/src/version.c
+++ b/src/version.c
@@ -795,6 +795,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    270,
+/**/
     269,
 /**/
     268,