Increase the default font size of the grid to 9pt

Conforms to Microsoft's Win32 UX guidelines.
https://learn.microsoft.com/en-us/windows/win32/uxguide/vis-fonts#fonts-and-colors

Author: 0tkl

src/libresrc/default_config.json

@@ -432,7 +432,7 @@
 			],
 			"Focus Allow" : true,
 			"Font Face" : "",
-			"Font Size" : 8,
+			"Font Size" : 9,
 			"Hide Overrides" : 1,
 			"Hide Overrides Char" : "★",
 			"Highlight Subtitles in Frame" : true