patch 8.0.1753: various warnings from a static analyser

Problem:    Various warnings from a static analyser
Solution:   Add type casts, remove unneeded conditions. (Christian Brabandt,
            closes #2770)
diff --git a/src/search.c b/src/search.c
index a4b2722..a346362 100644
--- a/src/search.c
+++ b/src/search.c
@@ -4071,7 +4071,7 @@
 	goto again;
     }
 
-    if (do_include || r < 1)
+    if (do_include)
     {
 	/* Include up to the '>'. */
 	while (*ml_get_cursor() != '>')