patch 8.0.0749: some unicode digraphs are hard to remember

Problem:    Some unicode digraphs are hard to remember.
Solution:   Add alternatives with a backtick. (Chris Harding, closes #1861)

src/digraph.c

@@ -1876,6 +1876,13 @@ static digr_T digraphdefault[] =
 	{'f', 'l', 0xfb02},
 	{'f', 't', 0xfb05},
 	{'s', 't', 0xfb06},
+
+	/* extra alternatives, easier to remember */
+	{'W', '`', 0x1e80},
+	{'w', '`', 0x1e81},
+	{'Y', '`', 0x1ef2},
+	{'y', '`', 0x1ef3},
+
 #      endif /* FEAT_MBYTE */
 
 	/* Vim 5.x compatible digraphs that don't conflict with the above */

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    749,
 /**/
     748,
 /**/