patch 8.1.1969: popup window filter is used in all modes

Problem:    Popup window filter is used in all modes.
Solution:   Add the "filtermode" property.
diff --git a/src/vim.h b/src/vim.h
index e9d586b..29441c8 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -680,6 +680,7 @@
 #define CONFIRM		0x800	// ":confirm" prompt
 #define SELECTMODE	0x1000	// Select mode, only for mappings
 #define TERMINAL        0x2000  // Terminal mode
+#define MODE_ALL	0xffff
 
 // all mode bits used for mapping
 #define MAP_ALL_MODES	(0x3f | SELECTMODE | TERMINAL)