patch 9.0.0007: no support for double, dotted and dashed underlines

Problem:    No support for double, dotted and dashed underlines.
Solution:   Add the termcap entries and highlight modes. (closes #9553)
diff --git a/src/vim.h b/src/vim.h
index 97ce639..a4da185 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -659,10 +659,13 @@
 #define HL_ITALIC		0x04
 #define HL_UNDERLINE		0x08
 #define HL_UNDERCURL		0x10
-#define HL_STANDOUT		0x20
-#define HL_NOCOMBINE		0x40
-#define HL_STRIKETHROUGH	0x80
-#define HL_ALL			0xff
+#define HL_UNDERDOUBLE		0x20
+#define HL_UNDERDOTTED		0x40
+#define HL_UNDERDASHED		0x80
+#define HL_STANDOUT		0x100
+#define HL_NOCOMBINE		0x200
+#define HL_STRIKETHROUGH	0x400
+#define HL_ALL			0x7ff
 
 // special attribute addition: Put message in history
 #define MSG_HIST		0x1000