docs(readme): fix the magic methods prefix __.

The magic methods prefix `__` was being automatically changed to `**` on save in vscode. So to prevent that, we need to escape the underscores.

Author: yCodeTech

README.md

@@ -200,7 +200,7 @@ Functions that return a value must have a `@return` docblock tag.
 
 -   Fixes with a <code>mixed</code> return type
 
--   Magic methods (e.g. <code>**construct</code>, <code>**get</code>, etc.) are exempt.
+-   Magic methods (e.g. <code>\_\_construct</code>, <code>\_\_get</code>, etc.) are exempt.
 
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