[Java.Interop.Tools.JavaSource] Better handle embedded html in html docs

We have a lot of instances in our docs where we are using HTML entities rather than the tag itself, for example:

* `A &lt;em&gt;lookup object&lt;/em&gt; is a factory`
* `An <c>ArrayList&lt;String&gt;</c> corresponding...`

We should consider using `<` and `>` characters in place of these entities, and/or scan usage for more common HTML elements that can be converted to C# doc elements.