patch 8.0.1809: various typos

Problem:    Various typos.
Solution:   Correct the mistakes, change "cursur" to "cursor". (closes #2887)
diff --git a/src/normal.c b/src/normal.c
index be0e75e..3b958a5 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -7797,7 +7797,7 @@
 {
 #ifdef FEAT_CONCEAL
     /* Check for redraw before changing the state. */
-    conceal_check_cursur_line();
+    conceal_check_cursor_line();
 #endif
 
     VIsual_mode = c;
@@ -7824,7 +7824,7 @@
 #endif
 #ifdef FEAT_CONCEAL
     /* Check for redraw after changing the state. */
-    conceal_check_cursur_line();
+    conceal_check_cursor_line();
 #endif
 
     if (p_smd && msg_silent == 0)