Fixed #17638 -- Added crosslinks between topic and reference guides.

Thanks oinopion for the suggestion and jarus for the initial patch.

docs/ref/class-based-views/index.txt

@@ -2,8 +2,8 @@
 Built-in Class-based views API
 ==============================
 
-Class-based views API reference. For introductory material, see
-:doc:`/topics/class-based-views/index`.
+Class-based views API reference. For introductory material, see the
+:doc:`/topics/class-based-views/index` topic guide.
 
 .. toctree::
    :maxdepth: 3

docs/ref/forms/formsets.txt

@@ -1,6 +1,9 @@
-====================
+=================
 Formset Functions
-====================
+=================
+
+Formset API reference. For introductory material about formsets, see the
+:doc:`/topics/forms/formsets` topic guide.
 
 .. module:: django.forms.formsets
    :synopsis: Django's functions for building formsets.

docs/ref/forms/index.txt

@@ -2,7 +2,8 @@
 Forms
 =====
 
-Detailed form API reference. For introductory material, see :doc:`/topics/forms/index`.
+Detailed form API reference. For introductory material, see the
+:doc:`/topics/forms/index` topic guide.
 
 .. toctree::
    :maxdepth: 2

docs/ref/forms/models.txt

@@ -2,6 +2,9 @@
 Model Form Functions
 ====================
 
+Model Form API reference. For introductory material about model forms, see the
+:doc:`/topics/forms/modelforms` topic guide.
+
 .. module:: django.forms.models
    :synopsis: Django's functions for building model forms and formsets.
 

docs/ref/migration-operations.txt

@@ -28,6 +28,9 @@ output incorrect code.
 All of the core Django operations are available from the
 ``django.db.migrations.operations`` module.
 
+For introductory material, see the :doc:`migrations topic guide
+</topics/migrations>`.
+
 Schema Operations
 =================
 

docs/ref/settings.txt

@@ -18,7 +18,8 @@ Core settings
 
 Here's a list of settings available in Django core and their default values.
 Settings provided by contrib apps are listed below, followed by a topical index
-of the core settings.
+of the core settings. For introductory material, see the :doc:`settings topic
+guide </topics/settings>`.
 
 .. setting:: ABSOLUTE_URL_OVERRIDES
 

docs/ref/templates/index.txt

@@ -5,7 +5,8 @@ Templates
 Django's template engine provides a powerful mini-language for defining the
 user-facing layer of your application, encouraging a clean separation of
 application and presentation logic. Templates can be maintained by anyone with
-an understanding of HTML; no knowledge of Python is required.
+an understanding of HTML; no knowledge of Python is required. For introductory
+material, see :doc:`/topics/templates` topic guide.
 
 .. toctree::
    :maxdepth: 2