Add bash completion for spring command

* Added src/main/content/bash_completion.d/spring
* Also made all commands alias to "--<self>" so
"--help" is a synonym for "help" (for instance). This
helps with the completion generation.

[Fixes #54827292]

spring-boot-cli/src/test/java/org/springframework/boot/cli/command/OptionParsingCommandTests.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2012-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.cli.command;
+
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.junit.Assert.assertThat;
+
+/**
+ * @author Dave Syer
+ */
+public class OptionParsingCommandTests {
+
+	@Test
+	public void optionHelp() {
+		OptionHandler handler = new OptionHandler();
+		handler.option("bar", "Bar");
+		OptionParsingCommand command = new OptionParsingCommand("foo", "Foo", handler) {
+		};
+		assertThat(command.getHelp(), containsString("--bar"));
+	}
+
+}