fix links

docs/backends.rst

@@ -11,10 +11,10 @@ backend. This enables transparent acceleration of the solution phase with
 OpenMP, OpenCL, CUDA, or any other technologies.
 
 In order to use a backend, user must include its definition from the
-corresponding file inside `amgcl/backend/`_ folder. On the user side of things,
+corresponding file inside `amgcl/backend`_ folder. On the user side of things,
 only the types of the right-hand side and the solution vectors should be
 affected by the choice of AMGCL backend. Here is an example of using the
-:cpp:struct:`builtin <amgcl::backend::builtin>` backend. First, we need to
+:cpp:class:`builtin <amgcl::backend::builtin>` backend. First, we need to
 include the appropriate header:
 
 .. code-block:: cpp
@@ -43,7 +43,7 @@ Now, if we want to switch to a different backend, for example, in order to
 accelerate the solution phase with a powerful GPU, we just need to include
 another backend header, and change the definitions of ``Backend``, ``rhs``,
 and ``x``. Here is an example of what needs to be done to use the
-:cpp:struct:`VexCL <amgcl::backend::vexcl>` backend.
+:cpp:class:`VexCL <amgcl::backend::vexcl>` backend.
 
 Include the correct header:
 
@@ -79,7 +79,7 @@ VexCL context to use:
     // Pass the parameters to the solver constructor:
     Solver solve(A, Solver::params(), backend_prm);
 
-.. _`amgcl/backend/`: https://github.com/ddemidov/amgcl/blob/master/amgcl/backend/
+.. _`amgcl/backend`: https://github.com/ddemidov/amgcl/blob/master/amgcl/backend/
 .. _`amgcl/backend/interface.hpp`: https://github.com/ddemidov/amgcl/blob/master/amgcl/backend/interface.hpp
 
 Builtin