patch 8.2.3914: various spelling mistakes in comments

Problem:    Various spelling mistakes in comments.
Solution:   Fix the mistakes. (Dominique Pellé, closes #9416)
diff --git a/src/terminal.c b/src/terminal.c
index 8f80f9f..a88e4bc 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -1591,7 +1591,7 @@
     {
 	job_T *job = term->tl_job;
 
-	// Careful: Checking the job status may invoked callbacks, which close
+	// Careful: Checking the job status may invoke callbacks, which close
 	// the buffer and terminate "term".  However, "job" will not be freed
 	// yet.
 	if (check_job_status)