Fix typos in reachability metadata gradle tasks descriptions (#463)

* metadataCopy: replaces 'metdata' with 'metadata'
* collectReachabilityMetadata: removes trailing dot to match all other task's descriptions

Author: abelsromero

native-gradle-plugin/src/main/java/org/graalvm/buildtools/gradle/NativeImagePlugin.java

@@ -276,7 +276,7 @@ private void configureJavaProject(Project project, Provider<NativeImageService>
 
         project.getTasks().register("metadataCopy", MetadataCopyTask.class, task -> {
             task.setGroup(LifecycleBasePlugin.BUILD_GROUP);
-            task.setDescription("Copies metadata collected from tasks instrumented with the agent into target directories.");
+            task.setDescription("Copies metadata collected from tasks instrumented with the agent into target directories");
             task.getInputTaskNames().set(graalExtension.getAgent().getMetadataCopy().getInputTaskNames());
             task.getOutputDirectories().set(graalExtension.getAgent().getMetadataCopy().getOutputDirectories());
             task.getMergeWithExisting().set(graalExtension.getAgent().getMetadataCopy().getMergeWithExisting());
@@ -285,7 +285,7 @@ private void configureJavaProject(Project project, Provider<NativeImageService>
 
         project.getTasks().register("collectReachabilityMetadata", CollectReachabilityMetadata.class, task -> {
             task.setGroup(LifecycleBasePlugin.BUILD_GROUP);
-            task.setDescription("Obtains native reachability metdata for the runtime classpath configuration");
+            task.setDescription("Obtains native reachability metadata for the runtime classpath configuration");
             task.setClasspath(project.getConfigurations().getByName(JavaPlugin.RUNTIME_CLASSPATH_CONFIGURATION_NAME));
         });