Fix type mismatch in documentation

Change-Id: Ief4d6a5039ea7af6f0b318df5146abe804611ca3

docs/source/nnls_solving.rst

diff --git a/docs/source/nnls_solving.rst b/docs/source/nnls_solving.rst
index 7f7340b..159bff0 100644
--- a/docs/source/nnls_solving.rst
+++ b/docs/source/nnls_solving.rst
@@ -2083,7 +2083,7 @@
    For each row ``i``, ``cols[rows[i]]`` ... ``cols[rows[i + 1] - 1]``
    are the indices of the non-zero columns of row ``i``.
 
-.. member:: vector<int> CRSMatrix::values
+.. member:: vector<double> CRSMatrix::values
 
    :member:`CRSMatrix::values` contain as many entries as there are
    non-zeros in the matrix.