[toolchain] Parsing support for struct literals, following #653.#699

Merged

zygoloid merged 9 commits intocarbon-language:trunkfrom zygoloid:toolchain

Aug 28, 2021

+269-24

Commits on Aug 3, 2021

Commits on Aug 6, 2021

Split enum type out of variable declaration.
zygoloid
committed

Commits on Aug 11, 2021

Switch from {name: type} to {.name: type} for struct types.
zygoloid
committed

Commits on Aug 12, 2021

Commits on Aug 28, 2021

Add testing for junk at the end of a struct literal.
zygoloid
committed