patch 8.1.0528: various typos in comments

Problem:    Various typos in comments.
Solution:   Fix the typos.
diff --git a/src/gui_w32.c b/src/gui_w32.c
index 95fe0cb..0db57ac 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -5658,7 +5658,7 @@
     HMONITOR	    mon;
     MONITORINFO	    moninfo;
 
-    /* work out which monitor the window is on, and get *it's* work area */
+    /* work out which monitor the window is on, and get *its* work area */
     mon = MonitorFromWindow(s_hwnd, MONITOR_DEFAULTTOPRIMARY);
     if (mon != NULL)
     {