Support string alias type's ToStringE and ToString functions

[PeterlitsZo]

Now we support:

type StrAlias string
ToString(StrAlias("bar")) // "bar"

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[PeterlitsZo]

Oops, I am sorry that I ask for PR in wrong space... BTW, do you want my PR? If you do, I will change it for your project or you can just close the PR directly.

[xiaotushaoxia]

i dont think this is a good pr. same problem in all others type alias.

type uintAlias uint16
ToString(uintAlias (1)) // "1"