Add new mvn alias for mvn fmt:format (#9053)

* mvn: add mvnfmt alias

* mvn: update README.md

plugins/mvn/mvn.plugin.zsh

@@ -59,6 +59,7 @@ alias mvnd='mvn deploy'
 alias mvndocs='mvn dependency:resolve -Dclassifier=javadoc'
 alias mvndt='mvn dependency:tree'
 alias mvne='mvn eclipse:eclipse'
+alias mvnfmt='mvn fmt:format'
 alias mvnjetty='mvn jetty:run'
 alias mvnp='mvn package'
 alias mvns='mvn site'