feat(fonts): rename manager to format

Author: RossComputerGuy

src/phantom/fonts.zig

@@ -1,7 +1,7 @@
 const std = @import("std");
 
 pub const Font = @import("fonts/font.zig");
-pub const Manager = @import("fonts/manager.zig");
+pub const Format = @import("fonts/format.zig");
 
 pub const backends = @import("fonts/backends.zig");
 pub const BackendType = std.meta.DeclEnum(backends);