patch 8.0.1550: various small problems in source files

Problem:    Various small problems in source files.
Solution:   Fix the problems.
diff --git a/src/if_xcmdsrv.c b/src/if_xcmdsrv.c
index 2d87e30..af2e672 100644
--- a/src/if_xcmdsrv.c
+++ b/src/if_xcmdsrv.c
@@ -1123,7 +1123,7 @@
  * This procedure is invoked by the various X event loops throughout Vims when
  * a property changes on the communication window.  This procedure reads the
  * property and enqueues command requests and responses. If immediate is true,
- * it runs the event immediatly instead of enqueuing it. Immediate can cause
+ * it runs the event immediately instead of enqueuing it. Immediate can cause
  * unintended behavior and should only be used for code that blocks for a
  * response.
  */