[9.x] Improve Support\LazyCollection type definitions (#39506)

* Make LazyCollection generic

* Remove `toBase` type test from LazyCollection

src/Illuminate/Collections/Collection.php

@@ -66,7 +66,7 @@ public function all()
     /**
      * Get a lazy collection for the items in this collection.
      *
-     * @return \Illuminate\Support\LazyCollection
+     * @return \Illuminate\Support\LazyCollection<TKey, TValue>
      */
     public function lazy()
     {
@@ -366,7 +366,7 @@ public function filter(callable $callback = null)
      *
      * @template TFirstDefault
      *
-     * @param  (callable(TValue): bool)|null  $callback
+     * @param  (callable(TValue, TKey): bool)|null  $callback
      * @param  TFirstDefault  $default
      * @return TValue|TFirstDefault
      */
@@ -1188,10 +1188,10 @@ public function sole($key = null, $operator = null, $value = null)
     /**
      * Get the first item in the collection but throw an exception if no matching items exist.
      *
-     * @param  mixed  $key
+     * @param  (callable(TValue, TKey): bool)|string  $key
      * @param  mixed  $operator
      * @param  mixed  $value
-     * @return mixed
+     * @return TValue
      *
      * @throws \Illuminate\Support\ItemNotFoundException
      */
@@ -1216,7 +1216,7 @@ public function firstOrFail($key = null, $operator = null, $value = null)
      * Chunk the collection into chunks of the given size.
      *
      * @param  int  $size
-     * @return static<int, static<int, TValue>>
+     * @return static<int, static<TKey, TValue>>
      */
     public function chunk($size)
     {

src/Illuminate/Collections/Enumerable.php

@@ -458,7 +458,7 @@ public function whereInstanceOf($type);
      *
      * @template TFirstDefault
      *
-     * @param  (callable(TValue): bool)|null  $callback
+     * @param  (callable(TValue,TKey): bool)|null  $callback
      * @param  TFirstDefault  $default
      * @return TValue|TFirstDefault
      */
@@ -878,7 +878,7 @@ public function sole($key = null, $operator = null, $value = null);
      * Chunk the collection into chunks of the given size.
      *
      * @param  int  $size
-     * @return static<int, static<int, TValue>>
+     * @return static<int, static<TKey, TValue>>
      */
     public function chunk($size);
 
@@ -1047,8 +1047,10 @@ public function pad($size, $value);
     /**
      * Count the number of items in the collection using a given truth test.
      *
-     * @param  (callable(TValue, TKey): mixed)|string|null  $callback
-     * @return static<TValue, int>
+     * @template TGroup of array-key
+     *
+     * @param  (callable(TValue, TKey): TGroup)|string|null  $callback
+     * @return static<TGroup, int>
      */
     public function countBy($callback = null);