Add support for @Usage tags

Author: jigarius

src/Commands/ExecCommand.php

@@ -26,6 +26,10 @@ protected function configure() {
     $this->setDescription($task->getSummary());
     $this->setHelp($task->getDescription());
 
+    foreach ($task->getUsages() as $usage) {
+      $this->addUsage($usage);
+    }
+
     foreach ($task->getArguments() as $argument) {
       if (is_a($argument, BuiltInArgument::class)) {
         continue;

src/Task.php

@@ -45,6 +45,10 @@ public function getCommand(): string {
     return str_replace(['_', '\\'], ['-', ':'], $this->callback);
   }
 
+  public function getUsages(): array {
+    return $this->docblock->getTagsByName('usage');
+  }
+
   /**
    * Whether the task is exposed as a console command.
    *