Documented AllowEnableReload restriction for plugin hot-reload

Author: jankrassnigg

pages/docs/custom-code/cpp/cpp-code-reload.md

@@ -34,6 +34,7 @@ You can always manually restart the engine process through *Tools > Reload Engin
 
 The `Enable Reload` option should only be used for select game plugins. Enabling this feature can have unintended side-effects.
 
+* The `Enable Reload` checkbox is only available for plugins that explicitly support it. For all other plugins it is greyed out in the [plugin selection](../../projects/plugin-selection.md) dialog. A plugin can opt in by setting `AllowEnableReload` to `true` in its [ezPluginBundle file](../../projects/plugin-selection.md#ezpluginbundle-files).
 * If any code links against a plugin, that plugin cannot be loaded as a copy. Therefore, if you want to put shared code into a separate library that other users of your plugins link against, you can't load that shared library as a copy.
 * You can't compile code while debugging a process. To compile your code, you first have to detach your debugger. In Visual Studio that can be done via `Debug > Detach All`.
 * Consequently, if you want to continue debugging after you restarted the engine process, you need to manually re-attach your debugger to *ezEditorEngineProcess.exe*. In Visual Studio this is done via `Debug > Attach to Process...` or even better `Debug > Reattach to Process` (`SHIFT+ALT+P`) when you want to repeat the same thing a second time.

pages/docs/projects/plugin-selection.md

@@ -21,6 +21,8 @@ Enable the checkmark for a plugin to make it active in this project.
 
 If you *Enable Reload* for a plugin, the engine will load a copy of the runtime plugin DLL, rather than the original DLL. This allows to edit and compile the DLL while the editor is running. Typically, this should only be active for a single, game-specific plugin. See [Hot Reloading C++ Game Plugins in the Editor](../custom-code/cpp/cpp-code-reload.md) for details.
 
+This option is only available for plugins that explicitly support it. The checkbox is greyed out for plugins that do not. A plugin opts in by setting `AllowEnableReload` to `true` in its [ezPluginBundle file](#ezpluginbundle-files). This should only be done for plugins that are loaded purely dynamically at runtime and not linked against directly.
+
 ## Custom Plugin Entries
 
 If you have a [custom plugin](../custom-code/cpp/engine-plugins.md) that should show up in this list, you need to add an `ezPluginBundle` file.