docs: update Model join signature and use literalinclude (#9070)

Author: wakqasahmed

system/Model.php

@@ -62,7 +62,7 @@
  * @method $this havingLike($field, string $match = '', string $side = 'both', ?bool $escape = null, bool $insensitiveSearch = false)
  * @method $this havingNotBetween(?string $key = null, array<array-key, mixed>|null $values = null, ?bool $escape = null)
  * @method $this havingNotIn(?string $key = null, $values = null, ?bool $escape = null)
- * @method $this join(string $table, string $cond, string $type = '', ?bool $escape = null)
+ * @method $this join(RawSql|string $table, RawSql|string $cond, string $type = '', ?bool $escape = null)
  * @method $this like($field, string $match = '', string $side = 'both', ?bool $escape = null, bool $insensitiveSearch = false)
  * @method $this likeAny(list<RawSql|string> $fields, string $match = '', string $side = 'both', ?bool $escape = null, bool $insensitiveSearch = false)
  * @method $this limit(?int $value = null, ?int $offset = 0)

user_guide_src/source/database/query_builder.rst

@@ -304,15 +304,7 @@ Since v4.2.0, ``$builder->join()`` accepts a ``CodeIgniter\Database\RawSql`` ins
 Since v4.8.0, the table can also be a ``RawSql`` instance. For example, you
 can join a subquery:
 
-.. code-block:: php
-
-    use CodeIgniter\Database\RawSql;
-
-    $builder->join(
-        new RawSql('(SELECT user_id, MAX(created_at) AS latest FROM posts GROUP BY user_id) recent'),
-        'recent.user_id = users.id',
-        'LEFT'
-    );
+.. literalinclude:: query_builder/134.php
 
 .. warning:: When you use ``RawSql``, you MUST escape the values and protect the identifiers manually. Failure to do so could result in SQL injections.
 

user_guide_src/source/database/query_builder/134.php

@@ -0,0 +1,9 @@
+<?php
+
+use CodeIgniter\Database\RawSql;
+
+$builder->join(
+    new RawSql('(SELECT user_id, MAX(created_at) AS latest FROM posts GROUP BY user_id) recent'),
+    'recent.user_id = users.id',
+    'LEFT',
+);