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

[pjcollins]

We have a lot of instances in our docs where we are using HTML entities rather than the tag itself, for example:

• A <em>lookup object</em> 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.