add match guards (#9621)

## description

this pr adds [match
guards](https://doc.rust-lang.org/reference/expressions/match-expr.html#match-guards)
to match patterns
```nushell
match $x {
   _ if $x starts-with 'nu' => {},
   $x => {}
}
```

these work pretty much like rust's match guards, with few limitations:

1. multiple matches using the `|` are not (yet?) supported
 
```nushell
match $num {
    0 | _ if (is-odd $num) => {},
    _ => {}
}
```

2. blocks cannot be used as guards, (yet?)

```nushell
match $num {
    $x if { $x ** $x == inf } => {},
     _ => {}
}
```

## checklist
- [x] syntax
- [x] syntax highlighting[^1]
- [x] semantics
- [x] tests
- [x] clean up

[^1]: defered for another pr

crates/nu-command/tests/commands/match_.rs

@@ -197,3 +197,54 @@ fn match_doesnt_overwrite_variable() {
     // As we do not auto-print loops anymore
     assert_eq!(actual.out, "100");
 }
+
+#[test]
+fn match_with_guard() {
+    let actual = nu!(
+        cwd: ".",
+        "match [1 2 3] { [$x, ..] if $x mod 2 == 0 => { $x }, $x => { 2 } }"
+    );
+
+    assert_eq!(actual.out, "2");
+}
+
+#[test]
+fn match_with_guard_block_as_guard() {
+    // this should work?
+    let actual = nu!(
+        cwd: ".",
+        "match 4 { $x if { $x + 20 > 25 } => { 'good num' }, _ => { 'terrible num' } }"
+    );
+
+    assert!(actual.err.contains("Match guard not bool"));
+}
+
+#[test]
+fn match_with_guard_parens_expr_as_guard() {
+    let actual = nu!(
+        cwd: ".",
+        "match 4 { $x if ($x + 20 > 25) => { 'good num' }, _ => { 'terrible num' } }"
+    );
+
+    assert_eq!(actual.out, "terrible num");
+}
+
+#[test]
+fn match_with_guard_not_bool() {
+    let actual = nu!(
+        cwd: ".",
+        "match 4 { $x if $x + 1 => { 'err!()' }, _ => { 'unreachable!()' } }"
+    );
+
+    assert!(actual.err.contains("Match guard not bool"));
+}
+
+#[test]
+fn match_with_guard_no_expr_after_if() {
+    let actual = nu!(
+        cwd: ".",
+        "match 4 { $x if  => { 'err!()' }, _ => { 'unreachable!()' } }"
+    );
+
+    assert!(actual.err.contains("Match guard without an expression"));
+}