fix theano.sparse.mul docs

change `+` with `*`

fix theano.sparse.mul docs
bcf999fe · Michael Manukyan · GitHub · 67cd4234 · bcf999fe
--- a/theano/sparse/basic.py
+++ b/theano/sparse/basic.py
@@ -2419,7 +2419,7 @@ def mul(x, y):
    Returns
    -------
    A sparse matrix
-        `x` + `y`
+        `x` * `y`
    Notes
    -----