Fix match example whitespace (#9961)

I was looking up `match` documentation and noticed that the formatting
was a bit off for the last example (starts on the wrong line, is several
columns too far to the right).

## Before:

![image](https://github.com/nushell/nushell/assets/26268125/cea55875-894c-442f-aa93-d5c18a0cdfa5)

## After:


![image](https://github.com/nushell/nushell/assets/26268125/064c9f80-6a70-4748-a877-5344ec6e6a80)

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

@@ -121,8 +121,7 @@ impl Command for Match {
             },
             Example {
                 description: "Match with a guard",
-                example: "
+                example: "match [1 2 3] {
-                    match [1 2 3] {
         [$x, ..$y] if $x == 1 => { 'good list' },
         _ => { 'not a very good list' }
     }