patch 9.0.1453: typos in source code and tests

Problem:    Typos in source code and tests.
Solution:   Fi the typos. (Dominique Pellé, closes #12217)
diff --git a/src/testdir/test_menu.vim b/src/testdir/test_menu.vim
index 1247359..9929dd5 100644
--- a/src/testdir/test_menu.vim
+++ b/src/testdir/test_menu.vim
@@ -162,7 +162,7 @@
 
 " Test for menu item completion in command line
 func Test_menu_expand()
-  " Create the menu itmes for test
+  " Create the menu items for test
   menu Dummy.Nothing lll
   for i in range(1, 4)
     let m = 'menu Xmenu.A' .. i .. '.A' .. i
diff --git a/src/testdir/test_mswin_event.vim b/src/testdir/test_mswin_event.vim
index e2add3b..4de0169 100644
--- a/src/testdir/test_mswin_event.vim
+++ b/src/testdir/test_mswin_event.vim
@@ -6,7 +6,7 @@
 source mouse.vim
 
 " Helper function for sending a grouped sequence of low level key presses
-" The modifer key(s) can be included as VK Key Codes in the sequence
+" The modifier key(s) can be included as VK Key Codes in the sequence
 " Keydown events will be sent, to to the end of the group, then keyup events
 " will be sent in reverse order to release the keys.
 func SendKeyGroup(keygroup)
@@ -19,7 +19,7 @@
 endfunc
 
 " Send individual key press and release events.
-" the modifers for the key press can be specified in the modifiers arg.
+" the modifiers for the key press can be specified in the modifiers arg.
 func SendKeyWithModifiers(key, modifiers)
   let args = { }
   let args.keycode = a:key
@@ -359,7 +359,7 @@
     " and when the virtual termcap maps the character
     call assert_equal(0, mod_mask, $"key = {kstr}")
 
-    " Send as a single key press with a modifers mask.
+    " Send as a single key press with a modifiers mask.
     let modifiers = 0
     let key = kcodes[0]
     for key in kcodes
diff --git a/src/testdir/test_textprop.vim b/src/testdir/test_textprop.vim
index cd141eb..3d196d9 100644
--- a/src/testdir/test_textprop.vim
+++ b/src/testdir/test_textprop.vim
@@ -1570,7 +1570,7 @@
   call prop_add(2, 7, {'length': 2, 'type': 'number'})
   call prop_add(3, 6, {'length': 2, 'type': 'number'})
   call prop_add(4, 7, {'length': 2, 'type': 'number'})
-  " The highlighted "is" in line 1, 2 and 4 is kept and ajudsted.
+  " The highlighted "is" in line 1, 2 and 4 is kept and adjusted.
   " The highlighted "is" in line 3 is deleted.
   let expected = [
         \ #{type_bufnr: 0, id: 0, col: 6, end: 1, type: 'number', length: 2, start: 1},