Problem with special characters on sections' id and link's href

[newtoncalegari]

There is a problem on TOC links href when using special characters such as accented letters on sections titles.

Steps to reproduce:

1. Create a section that uses special characters, such as: "Diagnóstico"
2. Generate a new TOC

What happens:

It lowercases the word and set the header id as id="diagnóstico", but when setting the the TOC item href, it removes the special letter and set as href="diagnstico".

Example:

Header ID:

<h4 id="análise-diagnóstica">Análise diagnóstica</h4>

Link href:

<li><a href="#anlise-diagnstica">Análise diagnóstica</a></li>