update try command's help (#13173)

# Description

This PR updates the `try` command to show that `catch` is a closure and
can be used as such.

### Before

![image](https://github.com/nushell/nushell/assets/343840/dc330b10-cd68-4d70-9ff8-aa1e7cbda5f3)

### After

![image](https://github.com/nushell/nushell/assets/343840/146a7514-6026-4b53-bdf0-603c77c8a259)


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crates/nu-cmd-lang/src/core_commands/try_.rs

@@ -10,7 +10,7 @@ impl Command for Try {
     }
 
     fn usage(&self) -> &str {
-        "Try to run a block, if it fails optionally run a catch block."
+        "Try to run a block, if it fails optionally run a catch closure."
     }
 
     fn signature(&self) -> nu_protocol::Signature {
@@ -18,7 +18,7 @@ impl Command for Try {
             .input_output_types(vec![(Type::Any, Type::Any)])
             .required("try_block", SyntaxShape::Block, "Block to run.")
             .optional(
-                "catch_block",
+                "catch_closure",
                 SyntaxShape::Keyword(
                     b"catch".to_vec(),
                     Box::new(SyntaxShape::OneOf(vec![
@@ -26,7 +26,7 @@ impl Command for Try {
                         SyntaxShape::Closure(Some(vec![SyntaxShape::Any])),
                     ])),
                 ),
-                "Block to run if try block fails.",
+                "Closure to run if try block fails.",
             )
             .category(Category::Core)
     }
@@ -85,9 +85,14 @@ impl Command for Try {
             },
             Example {
                 description: "Try to run a missing command",
-                example: "try { asdfasdf } catch { 'missing' } ",
+                example: "try { asdfasdf } catch { 'missing' }",
                 result: Some(Value::test_string("missing")),
             },
+            Example {
+                description: "Try to run a missing command and report the message",
+                example: "try { asdfasdf } catch { |err| $err.msg }",
+                result: None,
+            },
         ]
     }
 }