Parsing error on $a'

[chriselrod]

julia> CSTParser.parse(raw":($a')")
  1:6   quote
  1:5    brackets
  1:3     errortoken( CSTParser.UnexpectedToken)
  1:2        1:1   OP: $
  1:1       a
  3:3      OP: '

julia> CSTParser.parse(raw"$a'")
  1:3   errortoken( CSTParser.UnexpectedToken)
  1:2      1:1   OP: $
  1:1     a
  3:3    OP: '

julia> CSTParser.parse(raw"$a")
  1:2     1:1   OP: $
  1:1    a

julia> CSTParser.parse(raw"a'")
  1:2     1:1   OP: '
  1:1    a

:($a') is of course a legitimate Julia expr, e.g. when interpolating into an Expr in which you're taking the adjoint.

[pfitzseb]

Fixed by #380.