[valadoc] Wrong CSS is for Methords, Signals, etc etc, in Links.
In the generated documentation, where there is a {@link foo}
the background for that span in repeated, making the text be impossible to read.
This is the correct version for method:
method::before, .description a.method, .brief_description a.method {
background-image: url(method.svg);
background-repeat: no-repeat;
padding-left: 1.5em;
}