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/term.c b/src/term.c
index e97ec2c..4757d85 100644
--- a/src/term.c
+++ b/src/term.c
@@ -4460,7 +4460,7 @@
 #endif
 #if defined(CHECK_DOUBLE_CLICK) || defined(PROTO)
 /*
- * Checking for double clicks ourselves.
+ * Checking for double-clicks ourselves.
  * "orig_topline" is used to avoid detecting a double-click when the window
  * contents scrolled (e.g., when 'scrolloff' is non-zero).
  */