improved readability for aliasedPivotColumns (#55055)

- use a new line for all chained Collection methods. easier to grok and much better diffs
- use short closure for simple `map` call
- utilize array unpacking to instantiate the Collection and avoid temporary variables

Author: browner12

src/Illuminate/Database/Eloquent/Relations/BelongsToMany.php

@@ -924,11 +924,14 @@ protected function shouldSelect(array $columns = ['*'])
      */
     protected function aliasedPivotColumns()
     {
-        $defaults = [$this->foreignPivotKey, $this->relatedPivotKey];
-
-        return (new BaseCollection(array_merge($defaults, $this->pivotColumns)))->map(function ($column) {
-            return $this->qualifyPivotColumn($column).' as pivot_'.$column;
-        })->unique()->all();
+        return (new BaseCollection([
+            $this->foreignPivotKey,
+            $this->relatedPivotKey,
+            ...$this->pivotColumns,
+        ]))
+            ->map(fn ($column) => $this->qualifyPivotColumn($column).' as pivot_'.$column)
+            ->unique()
+            ->all();
     }
 
     /**

src/Illuminate/Database/Eloquent/Relations/MorphToMany.php

@@ -178,11 +178,15 @@ public function newPivot(array $attributes = [], $exists = false)
      */
     protected function aliasedPivotColumns()
     {
-        $defaults = [$this->foreignPivotKey, $this->relatedPivotKey, $this->morphType];
-
-        return (new Collection(array_merge($defaults, $this->pivotColumns)))->map(function ($column) {
-            return $this->qualifyPivotColumn($column).' as pivot_'.$column;
-        })->unique()->all();
+        return (new Collection([
+            $this->foreignPivotKey,
+            $this->relatedPivotKey,
+            $this->morphType,
+            ...$this->pivotColumns,
+        ]))
+            ->map(fn ($column) => $this->qualifyPivotColumn($column).' as pivot_'.$column)
+            ->unique()
+            ->all();
     }
 
     /**