alias st for status, hide stf

stf should be found in the status docs rather than listed as a seperate 
command.

Author: schacon

crates/but/src/args.rs

@@ -19,13 +19,15 @@ pub enum Subcommands {
     /// Provides an overview of the Workspace commit graph.
     Log,
     /// Overview of the uncommitted changes in the repository.
+    #[clap(alias = "st")]
     Status {
         /// Determines whether the committed files should be shown as well.
         #[clap(short = 'f', alias = "files", default_value_t = false)]
         show_files: bool,
     },
     /// Overview of the uncommitted changes in the repository with files shown.
     /// Equivalent to `but status --files`.
+    #[clap(hide = true)]
     Stf,
 
     /// Combines two entities together to perform an operation.