Preferences Dialog: drop characters_per_line from hotkey list

[ci skip]

For some reason, this made the entire page stack thinner than it should be. I have
no idea why, and I'm not sure wrap= here instead does anything (namely, wrap if it
gets too long), but it's better than what was happening before.

data/gui/window/preferences/02_hotkeys.cfg

@@ -163,7 +163,7 @@
 												id = "lbl_desc"
 												definition = "gold_small"
 												linked_group = "hotkeys_col_desc"
-												characters_per_line = 30
+												wrap = true
 											[/label]
 										[/column]