coercion of Laurent series to SR

[rwst]

#16203 deals with conversion from Expression.series to PowerSeries but this should work too:

sage: R.<x> = LaurentSeriesRing(QQ)
sage: (1/(1-y)).series(y,5)
1 + 1*y + 1*y^2 + 1*y^3 + 1*y^4 + Order(y^5)
sage: _.subs(y=x)
TypeError: no canonical coercion from Laurent Series Ring in x over Rational Field to Symbolic Ring

or:

sage: (1/(1-y)).series(x,5)
(same error)

Component: symbolics

Issue created by migration from https://trac.sagemath.org/ticket/18500