Remove @desc tag in ESDoc comments for method definitions

[arnellebalane]

The first paragraph in the comment is already treated as the description for the method (please verify this though by checking the generated docs).

Currently affected methods are:

• all
• any
• append
• assoc
• at

Also update the descriptions remove <br> tags and instead use multiple paragraphs directly, e.g.

Before:

/**
 *  Lorem ipsum dolor...<br>This is another paragraph...
 */

After:

/**
 *  Lorem ipsum dolor...
 *
 *  This is another paragraph...
 */