patch 9.0.0828: various typos

Problem:    Various typos.
Solution:   Correct typos. (closes #11432)
diff --git a/src/testdir/test_cmdmods.vim b/src/testdir/test_cmdmods.vim
index eb6dff1..d5a4e93 100644
--- a/src/testdir/test_cmdmods.vim
+++ b/src/testdir/test_cmdmods.vim
@@ -1,4 +1,4 @@
-" Test for all comand modifiers in 
+" Test for all command modifiers in
 
 def Test_cmdmods_array()
   # Get all the command modifiers from ex_cmds.h.