patch 8.2.2160: various typos

Problem:    Various typos.
Solution:   Fix spelling mistakes. (closes #7494)
diff --git a/src/list.c b/src/list.c
index 6285e01..1c41f07 100644
--- a/src/list.c
+++ b/src/list.c
@@ -2693,7 +2693,7 @@
 }
 
 /*
- * "reduce(list, { accumlator, element -> value } [, initial])" function
+ * "reduce(list, { accumulator, element -> value } [, initial])" function
  */
     void
 f_reduce(typval_T *argvars, typval_T *rettv)