dillon1000/react

[new-arch] HIR cleanup per discussion

* Renames `Capability` to `Effect` and clarifies the kinds as Freeze, Read, and 
Mutate. The real intent of what we're inferring/representing is "what effect 
does this reference to the value have on its value". Ie freeze freezes the 
value, mutate mutates it. 

* Consolidates Capability and EffectKind into Effect 

* Renames some properties on Place for clarity 

* Adds `value: ValueKind` to Place, which indicates the (merged) kind of the 
value at that place at that point in the program. 

* Changes HIR printing to show the effect and the value kind 

* Simplifies some inference logic