Code highlight in docs for PhpStorm

docs/topics/accessing-cells.md

@@ -56,7 +56,7 @@ the cell object will still retain its data values.
 
 What does this mean? Consider the following code:
 
-```
+```php
 $spreadSheet = new Spreadsheet();
 $workSheet = $spreadSheet->getActiveSheet();
 
@@ -153,7 +153,7 @@ was a formula.
 
 To do this, you need to "escape" the value by setting it as "quoted text".
 
-```
+```php
 // Set cell A4 with a formula
 $spreadsheet->getActiveSheet()->setCellValue(
     'A4',

docs/topics/calculation-engine.md

@@ -55,7 +55,7 @@ However, there may be times when you don't want this, perhaps you've changed
 the underlying data and need to re-evaluate the same formula with that new
 data.
 
-```
+```php
 Calculation::getInstance($spreadsheet)->disableCalculationCache();
 ```
 
@@ -63,7 +63,7 @@ Will disable calculation caching, and flush the current calculation cache.
 
 If you want only to flush the cache, then you can call
 
-```
+```php
 Calculation::getInstance($spreadsheet)->clearCalculationCache();
 ```