Error in addeq! for MatAlgebraElem

[Lax202]

The function seems to update only coefficients and not the matrix itself.

julia> R = matrix_algebra(QQ,2)
Matrix algebra of dimension 4 over Rational field

julia> b = R(matrix(QQ,[3 4; 5 6]))
[3 4; 5 6]

julia> Hecke.addeq!(b,b)
[3 4; 5 6]

julia> b.coeffs
4-element Vector{QQFieldElem}:
 6
 10
 8
 12