patch 9.1.0476: Cannot see matched text in popup menu

Problem:  Cannot see matched text in popup menu
Solution: Introduce 2 new highlighting groups: PmenuMatch and
          PmenuMatchSel (glepnir)

ping @habamax, @neutaaaaan @romainl because vim/colorschemes may need
some updates, @lifepillar for updating vim-colortemplate

closes: #14694

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/insexpand.c b/src/insexpand.c
index 19a4a21..74be94c 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -1432,6 +1432,15 @@
 #define DICT_EXACT	(2)	// "dict" is the exact name of a file
 
 /*
+ * Get current completion leader
+ */
+    char_u *
+ins_compl_leader(void)
+{
+    return compl_leader;
+}
+
+/*
  * Add any identifiers that match the given pattern "pat" in the list of
  * dictionary files "dict_start" to the list of completions.
  */