Add missing comments to fkey.c. Also, change the terminology used for comments and names in fkey.c from "referenced/referencing" to "parent/child". This is arguably less correct, but is easier to follow.

FossilOrigin-Name: 540c2d18e14c277b55f95729fbafc04ca66466b2
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 17aed29..b028efe 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1290,11 +1290,8 @@
   FKey *pPrevTo;    /* Previous foreign key on table named zTo */
   int nCol;         /* Number of columns in this key */
   u8 isDeferred;    /* True if constraint checking is deferred till COMMIT */
-  u8 updateConf;    /* How to resolve conflicts that occur on UPDATE */
-  u8 deleteConf;    /* How to resolve conflicts that occur on DELETE */
-  u8 insertConf;    /* How to resolve conflicts that occur on INSERT */
-  Trigger *pOnUpdate;  /* Trigger for AFTER UPDATE ON zTo */
-  Trigger *pOnDelete;  /* Trigger for AFTER DELETE ON zTo */
+  u8 aAction[2];          /* ON DELETE and ON UPDATE actions, respectively */
+  Trigger *apTrigger[2];  /* Triggers for aAction[] actions */
   struct sColMap {  /* Mapping of columns in pFrom to columns in zTo */
     int iFrom;         /* Index of column in pFrom */
     char *zCol;        /* Name of column in zTo.  If 0 use PRIMARY KEY */