doc: use explicit references everywhere.
Doxygen: disable autolinking.

Finally.
doc: removed autolink-preventing % noise, removed unneeded HTML tags.
Math: removed autolink-preventing % noise, removed unneeded HTML tags.
Audio: removed autolink-preventing % noise.
DebugTools: removed autolink-preventing % noise.
MeshTools: removed autolink-preventing % noise.
Platform: removed autolink-preventing % noise.
Primitives: removed autolink-preventing % noise.
SceneGraph: removed autolink-preventing % noise, removed unneeded HTML.
Shaders: removed autolink-preventing % noise.
Shapes: removed autolink-preventing % noise.
Text: removed autolink-preventing % noise.
TextureTools: removed autolink-preventing % noise.
Trade: removed autolink-preventing % noise.
Removed autolink-preventing % noise and unneeded HTML from root namespace.
Removed autolink-preventing % noise from plugins.