AssemblyWatcher is an ILSpy plugin which reloads assemblies when they change.
Copy the AssemblyWatcher.Plugin.dll file into the same folder as ILSpy executable and restart ILSpy.
If the plugin is detected by ILSpy, you'll see an eye icon in the toolbar. This is a toggle button. Pressing it will enable watching of loaded assemblies. Pressing again will disable. When watching is enabled, and any of the loaded assemblies change on disk, the plugin refreshes all the assemblies.