Created Casting (markdown)

Casting.md

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+# Do not add spaces when casting
+
+The casting type should be put into parenthesis without spaces.
+
+<details><summary>Example</summary><div><br>
+
+**Bad**
+
+```PHP
+$text = ( string )$number;
+```
+
+**Good**
+
+```PHP
+$text = (string)$number;
+```
+
+</div></details><br>
+
+_Reference_: [`Squiz.WhiteSpace.CastSpacing`](https://github.com/squizlabs/PHP_CodeSniffer/blob/master/src/Standards/Squiz/Sniffs/WhiteSpace/CastSpacingSniff.php)