Imports of package versions

PathSynopsis
go/astPackage ast declares the types used to represent syntax trees for Go packages.
go/typesPackage types declares the data types and implements the algorithms for type-checking of Go packages.
go/versionPackage version provides operations on [Go versions] in [Go toolchain name syntax]: strings like "go1.20", "go1.21.0", "go1.22rc2", and "go1.23.4-bigcorp".
stringsPackage strings implements simple functions to manipulate UTF-8 encoded strings.