Add support for Postgres lquery arrays (#3553)

An lquery array can be used with the `?` operator for "Does ltree match
any lquery in array?"

Documentation: https://www.postgresql.org/docs/current/ltree.html#LTREE-OPS-FUNCS

Closes #2246

Author: philipcristiano

sqlx-postgres/src/types/lquery.rs

@@ -2,7 +2,7 @@ use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
 use crate::error::BoxDynError;
 use crate::types::Type;
-use crate::{PgArgumentBuffer, PgTypeInfo, PgValueFormat, PgValueRef, Postgres};
+use crate::{PgArgumentBuffer, PgHasArrayType, PgTypeInfo, PgValueFormat, PgValueRef, Postgres};
 use bitflags::bitflags;
 use std::fmt::{self, Display, Formatter};
 use std::io::Write;
@@ -161,6 +161,12 @@ impl Type<Postgres> for PgLQuery {
     }
 }
 
+impl PgHasArrayType for PgLQuery {
+    fn array_type_info() -> PgTypeInfo {
+        PgTypeInfo::with_name("_lquery")
+    }
+}
+
 impl Encode<'_, Postgres> for PgLQuery {
     fn encode_by_ref(&self, buf: &mut PgArgumentBuffer) -> Result<IsNull, BoxDynError> {
         buf.extend(1i8.to_le_bytes());