Add links to the packages list

Author: kwankyu

src/sage/databases/cubic_hecke_db.py

@@ -31,7 +31,8 @@
 of linear forms on the cubic Hecke algebra on at most four strands
 satisfying the Markov trace condition for its cubic Hecke subalgebras.
 
-To use the database, you need to install the optional package by the Sage
+To use the database, you need to install the optional
+:ref:`database_cubic_hecke <spkg_database_cubic_hecke>` package by the Sage
 command ::
 
     sage -i database_cubic_hecke

src/sage/databases/cunningham_tables.py

@@ -5,7 +5,8 @@
 numbers occurring in the factorization of numbers of type `b^n+1` or `b^n-1`
 with `b \in \{2,3,5,6,7,10,11,12\}`. For an introduction to Cunningham prime
 factors, see :wikipedia:`Cunningham_Project`. The data becomes available if you
-install the optional package by the command ::
+install the optional :ref:`cunningham_tables <cunningham_tables>` package by
+the command ::
 
     sage -i cunningham_tables
 

src/sage/databases/db_class_polynomials.py

@@ -1,8 +1,9 @@
 """
 Database of Hilbert polynomials
 
-This module gives access to the database of Hilbert class polynomials. To use the database, you need to install
-the optional package by the Sage command ::
+This module gives access to the database of Hilbert class polynomials. To use
+the database, you need to install the optional :ref:`database_kohel
+<database_kohel>` package by the Sage command ::
 
     sage -i database_kohel
 

src/sage/databases/db_modular_polynomials.py

@@ -2,7 +2,8 @@
 Database of modular polynomials
 
 This module gives access to the database of modular polynomials. To use the
-database, you need to install the optional package by the Sage command ::
+database, you need to install the optional :ref:`database_kohel
+<database_kohel>` package by the Sage command ::
 
     sage -i database_kohel
 

src/sage/databases/jones.py

@@ -1,8 +1,8 @@
 r"""
 John Jones's tables of number fields
 
-In order to use the Jones database, the optional database package
-must be installed using the Sage command ::
+In order to use the Jones database, the optional :ref:`database_jones_numfield
+<database_jones_numfield>` package must be installed using the Sage command ::
 
     sage -i database_jones_numfield
 

src/sage/databases/knotinfo_db.py

@@ -7,8 +7,8 @@
 at the web-pages `KnotInfo <https://knotinfo.math.indiana.edu/>`__ and
 `LinkInfo <https://linkinfo.sitehost.iu.edu>`__.
 
-To use the database, you need to install the optional package by the Sage
-command ::
+To use the database, you need to install the optional :ref:`database_knotinfo
+<database_knotinfo>` package by the Sage command ::
 
     sage -i database_knotinfo
 

src/sage/databases/odlyzko.py

@@ -3,7 +3,8 @@
 
 The main access function to the database of the zeros of the Riemann zeta
 function is :func:`zeta_zeros`. In order to use ``zeta_zeros()``, you need to
-install the optional Odlyzko database package::
+install the optional :ref:`database_odlyzko_zeta <database_odlyzko_zeta>`
+package::
 
     sage -i database_odlyzko_zeta
 

src/sage/databases/symbolic_data.py

@@ -31,8 +31,9 @@
     certified data that could be addressed and extended during further
     development.
 
-In order to use this dataset, you need to install the optional package
-by the Sage command ::
+In order to use this dataset, you need to install the optional
+:ref:`database_symbolic_data <database_symbolic_data>` package by the Sage
+command ::
 
     sage -i database_symbolic_data