Remove redundant spaces

Author: markstory

docs/en/appendices/5-4-migration-guide.md

@@ -16,7 +16,6 @@ bin/cake upgrade rector --rules cakephp54 <path/to/app/src>
 
 ## Behavior Changes
 
-
 ### Commands
 
 - `BaseCommand::initialize()` is now being triggered **AFTER** arguments and options have been parsed.
@@ -64,7 +63,6 @@ version is reported as `unknown`), the header is omitted.
 
 ## New Features
 
-
 ### Core
 
 - `PluginConfig::getInstalledPlugins()` was added to retrieve a list of all installed plugins