[temp.spec.partial.general], [temp.expl.spec] "Partial specialization" and "explicit specialization" should be defined

[Eisenwave]

I have noticed that we don't ever define these terms:

draft/source/templates.tex

Lines 3290 to 3291 in 9dc7b3f

	\indextext{specialization!class template partial}%
	A partial specialization of a template provides an alternative definition

draft/source/templates.tex

Lines 6524 to 6525 in 9dc7b3f

	\indextext{specialization!template explicit}%
	An explicit specialization of any of the following:

I imagine it would be better normatively if these terms were formal. Furthermore, I find it annoying that I can't Ctrl+F in the index and find explicit specialization or specialization, explicit that way.

Is there some reason why we don't do \defnadj{partial}{specialization} or something?

[frederick-vs-ja]

Also, the class template partial part is probably superfluous or outdated, as variable templates are also covered.