patch 9.0.0828: various typos

Problem:    Various typos.
Solution:   Correct typos. (closes #11432)
diff --git a/src/textprop.c b/src/textprop.c
index 808d1e6..dee35c3 100644
--- a/src/textprop.c
+++ b/src/textprop.c
@@ -900,7 +900,7 @@
     if (ht == NULL || ht->ht_used == 0)
 	return NULL;
 
-    // Make the loopup faster by creating an array with pointers to
+    // Make the lookup faster by creating an array with pointers to
     // hashtable entries, sorted on pt_id.
     if (*array == NULL)
     {