Order of color names affects whether parent entries are shown or not

[SametHope]

Unity Version: 6000.0.53f1
Package installed from the Package Manager via git URL: https://github.com/leth4/Colorlink.git

Issue:
When naming colors with slashes (/) to organize them into submenus, some entries don’t display correctly depending on their order:

• Case 1

  Foo
  Bar
  

  ✅ Two entries, as expected.

• Case 2

  Foo
  Foo/Bar
  

  ✅ Two entries: one submenu under Foo, one standalone Foo entry.

• Case 3

  Foo/Bar
  Foo
  

  ❌ Only one entry is displayed: Bar under Foo. The standalone Foo entry is missing.

This is probably caused by how entries are grouped and listed internally.

Proposal:
Sort or group entries in a way that preserves both standalone entries (e.g. Foo) and submenu entries (e.g. Foo/Bar), regardless of the order they are defined.