x.py: setup: Provide a description of what it does

Co-authored-by: Joshua Nelson <joshua@yottadb.com>

Author: ijackson

src/bootstrap/flags.rs

@@ -125,6 +125,7 @@ Subcommands:
     dist        Build distribution artifacts
     install     Install distribution artifacts
     run, r      Run tools contained in this repository
+    setup       Create a config.toml (making it easier to use `x.py` itself)
 
 To learn more about a subcommand, run `./x.py <subcommand> -h`",
         );
@@ -472,15 +473,21 @@ Arguments:
                 );
             }
             "setup" => {
-                subcommand_help.push_str(
+                subcommand_help.push_str(&format!(
                     "\n
+x.py setup creates a `config.toml` which changes the defaults for x.py itself.
+
 Arguments:
     This subcommand accepts a 'profile' to use for builds. For example:
 
         ./x.py setup library
 
-    The profile is optional and you will be prompted interactively if it is not given.",
-                );
+    The profile is optional and you will be prompted interactively if it is not given.
+    The following profiles are available:
+
+{}",
+                    Profile::all_for_help("        ").trim_end()
+                ));
             }
             _ => {}
         };