doxygen: Fix leading space in class member descriptions

doxygen: Fix leading space in class member descriptions

Using ResourceLoader.php as example:
 $ php maintenance/mwdoc-filter.php includes/resourceloader/ResourceLoader.php

== Before ==

Filtered code:

    /**  Associative mapping ... */ protected array $moduleInfos = array();

    /**  $config */ private Config $config;

Note descriptions containing a leading slash which was matched after the type
hint in the original code.

== After ==

Filtered code:

    /** Associative mapping ... */ protected array $moduleInfos = array();

    /** $config */ private Config $config;

Change-Id: Idcdd487ad0f4fbabdd5665abfbb8492f5bac655a