Should unescapePath function be documented

[slominskir]

It appears there is a secret function named unescapePath mentioned in issue #27, but not found in the latest documentation (v5.1 manual). If I'm understanding correctly this function is required to properly rewrite a URI path component to a URI query component in the event that the path contains a plus character. This is due to the confusing nature of a plus character in a URI path meaning plus whereas if found in a query component it means space. So it appears a rule to handle this scenario must unescape the path component (with special path rules) and then escape the query component (with special query rules) so looks like:

    <rule>
        <from>^/inventory/products/(.*)$</from>
        <to>/inventory/product-detail?name=${escape:${unescapePath:$1}}</to>
    </rule>

Did I get this right? Should this be documented?