fixup! refactor: extract modules from bot.zig

This comment was added when this refactoring had already been
performed.

src/buffer.zig

@@ -6,11 +6,6 @@ const std = @import("std");
 // automatically deinited when it is overwritten by supplying a custom
 // ItemDeinitClosure, using .init_with_closure.
 pub fn Buffer(comptime T: type, comptime length: usize) type {
-    // TODO(jassob): Refactor buffer to use a top and len instead of
-    // top and bottom.
-    //
-    // Idea: bottom is always 0 if len != length and otherwise it is
-    // always top + 1.
     return struct {
         items: [length]?T,
         top: usize,