mod: restructure terminal structs Key, Position and Size

src/terminal.zig

@@ -1,20 +1,11 @@
 const std = @import("std");
-pub const Key = @import("terminal/key.zig");
+pub const Key = @import("terminal/Key.zig");
+pub const Size = @import("terminal/Size.zig");
+pub const Position = @import("terminal/Position.zig");
 pub const code_point = @import("code_point");
 
 const log = std.log.scoped(.terminal);
 
-pub const Size = struct {
-    anchor: Position = .{ .col = 1, .row = 1 }, // top left corner by default
-    cols: u16,
-    rows: u16,
-};
-
-pub const Position = struct {
-    col: u16,
-    row: u16,
-};
-
 // Ref: https://vt100.net/docs/vt510-rm/DECRPM.html
 pub const ReportMode = enum {
     not_recognized,

src/terminal/Position.zig

@@ -0,0 +1,2 @@
+col: u16,
+row: u16,

src/terminal/Size.zig

@@ -0,0 +1,5 @@
+const Position = @import("Position.zig");
+
+anchor: Position = .{ .col = 1, .row = 1 }, // top left corner by default
+cols: u16,
+rows: u16,