Clean up dead links in sage/modular/ documentation

[davidloeffler]

Using the sage -docbuild --warn-links command reveals a bunch of broken links in the modular forms reference manual:

<autodoc>:1: WARNING: py:class reference target not found: sage.structure.parent_base.ParentWithBase
<autodoc>:1: WARNING: py:class reference target not found: sage.structure.parent_base.ParentWithBase
<autodoc>:1: WARNING: py:class reference target not found: sage.structure.parent_base.ParentWithBase
<autodoc>:1: WARNING: py:class reference target not found: sage.structure.parent_base.ParentWithBase
/storage/masiao/sage-5.0.beta10/local/lib/python2.7/site-packages/sage/modular/local_comp/smoothchar.py:docstring of sage.modular.local_comp.smoothchar.SmoothCharacterGroupRamifiedQuadratic.change_ring:1: WARNING: py:meth reference target not found: base_extend
/storage/masiao/sage-5.0.beta10/local/lib/python2.7/site-packages/sage/modular/local_comp/smoothchar.py:docstring of sage.modular.local_comp.smoothchar.SmoothCharacterGroupRamifiedQuadratic.ideal:1: WARNING: py:meth reference target not found: sage.rings.number_field.number_field_ideal.idealstar
/storage/masiao/sage-5.0.beta10/local/lib/python2.7/site-packages/sage/modular/local_comp/smoothchar.py:docstring of sage.modular.local_comp.smoothchar.SmoothCharacterGroupRamifiedQuadratic.ideal:1: WARNING: py:meth reference target not found: sage.rings.number_field.number_field_ideal.ideallog
/storage/masiao/sage-5.0.beta10/local/lib/python2.7/site-packages/sage/modular/local_comp/smoothchar.py:docstring of sage.modular.local_comp.smoothchar.SmoothCharacterGroupUnramifiedQuadratic.change_ring:1: WARNING: py:meth reference target not found: base_extend
/storage/masiao/sage-5.0.beta10/local/lib/python2.7/site-packages/sage/modular/local_comp/smoothchar.py:docstring of sage.modular.local_comp.smoothchar.SmoothCharacterGroupUnramifiedQuadratic.ideal:1: WARNING: py:meth reference target not found: sage.rings.number_field.number_field_ideal.idealstar
/storage/masiao/sage-5.0.beta10/local/lib/python2.7/site-packages/sage/modular/local_comp/smoothchar.py:docstring of sage.modular.local_comp.smoothchar.SmoothCharacterGroupUnramifiedQuadratic.ideal:1: WARNING: py:meth reference target not found: sage.rings.number_field.number_field_ideal.ideallog
/storage/masiao/sage-5.0.beta10/local/lib/python2.7/site-packages/sage/modular/modform/cuspidal_submodule.py:docstring of sage.modular.modform.cuspidal_submodule.CuspidalSubmodule.change_ring:1: WARNING: py:meth reference target not found: base_extend
docstring of sage.modular.modform.eis_series_cython.eisenstein_series_poly:1: WARNING: py:class reference target not found: sage.libs.flint.fmpz_poly.Fmpz_poly
<autodoc>:1: WARNING: py:class reference target not found: sage.structure.parent_base.ParentWithBase

[davidloeffler]

Patch against 5.0.beta10

[davidloeffler]

Here's a patch. To test this, on a clean Sage branch run the commands

sage -docbuild --warn-links reference html
sage -hg qimport http://trac.sagemath.org/sage_trac/raw-attachment/ticket/12757/trac_12757-fix_broken_links.patch 
sage -hg qpush
find devel/sage/sage/modular/ -name "*.py*" | xargs touch
sage -b
sage -docbuild --warn-links reference html

This will make Sphinx rebuild all files in sage/modular (plus one or two others touched by this ticket), and you can verify that they all build without warnings.

[AlexGhitza]

The warnings are gone. Looks good to me.

[davidloeffler]

Thanks for the review!