Change input/output types in help to a table (#9686)

# Description

Updates `help` to more clearly show input/output types.

Before:


![image](https://github.com/nushell/nushell/assets/547158/5f11ca5c-54a0-414d-b3de-1a8b4dd7fcbd)

After:


![image](https://github.com/nushell/nushell/assets/547158/afc0eb1e-fad8-43b1-9382-c2a0d8e9334e)

# User-Facing Changes

See above

# Tests + Formatting
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crates/nu-command/tests/commands/help.rs

@@ -20,13 +20,11 @@ fn help_commands_length() {
 #[test]
 fn help_shows_signature() {
     let actual = nu!("help str distance");
-    assert!(actual
-        .out
-        .contains("<string> | str distance <string> -> <int>"));
+    assert!(actual.out.contains("Input/output types"));
 
     // don't show signature for parser keyword
     let actual = nu!("help alias");
-    assert!(!actual.out.contains("Signatures"));
+    assert!(!actual.out.contains("Input/output types"));
 }
 
 #[ignore = "TODO: Need to decide how to do help messages of new aliases"]