arg attributes in MathML examples in open concept list (#67)

* arg attributes

* force inline display (subscript alignment) of hover tooltips

* highlight arg slots even on no hover

* some arity 3 fixes

* speech for therefore

* triangle number

* well formed mathml

* well formed mathml

* mismatched parens in ultrapower

* agr1 n cases

* missing quotes in yaml

* arity 2 matrix

* add intent attributes

* flag missing intent in red

* more intents

* more intents

* more intents arity 4

* more intents

* more intents

* mismatched brackets

* mismatched quote

* dihedral group

* direct-limit

* more mathml

* faber polynomial

* field of sets

* hypertorus

* hypertorus

* nth ...

* bijection arguments

* cap product

* spurious } in css #496

* arity 0 notations

* arity 3 notations

* arity 2 Work in Progress

* arity 1 Work in Progress

* no a2 in arity 1 stubs

* use star not n for n-ary to match core list

* more mathml

* double >>

* /mrow

* stalk

* stalk extra mrow

* surjection speech template

* derivation

* legendre poly

* col vector

* conditional-xxx

* mathml

* a9

* msup cases

* missing arg attributes

* missing arg attributes

* showmath

* preserve 

* mfrac cases

* yaml fixes

* wittaker 2 and 3

* wittaker W

* wittaker missing )

* wl mean

* wl mean

* avoid named entities

* typo

* msub cases

* more mathml

* more mathml

* more mathml

* yaml fixes

* pqr not prr

* rising/falling factorial

* mtable cases

* mtable cases

* m n not n n

* valid mathml

Author: davidcarlisle