Major doc cleanup:

- Reformat source so it's wrapped.
- Standardise markup.
- Center images.
- Restructure in various places to improve the indexing.
- Remove duplicated Query Tool toolbar descriptions.
- Ensure the structure works in both HTML and LaTeX.

docs/en_US/managing_database_objects.rst

@@ -4,14 +4,19 @@
 `Managing Database Objects`:index:
 **********************************
 
-pgAdmin 4 provides simple but powerful dialogs that you can use to design and create database objects.  Each dialog contains a series of tabs that you use to describe the object that will be created by the dialog; the SQL tab displays the SQL command that the server will execute when creating the object.
+pgAdmin 4 provides simple but powerful dialogs that you can use to design and
+create database objects.  Each dialog contains a series of tabs that you use to
+describe the object that will be created by the dialog; the SQL tab displays the
+SQL command that the server will execute when creating the object.
 
-To access a dialog that allows you to create a database object, right-click on the object type in the pgAdmin tree control, and select the *Create* option for that object.  For example, to create a new cast, right-click on the *Casts* node, and select *Create Cast...*
-
-Contents:
+To access a dialog that allows you to create a database object, right-click on
+the object type in the pgAdmin tree control, and select the *Create* option for
+that object.  For example, to create a new cast, right-click on the *Casts*
+node, and select *Create Cast...*
 
 .. toctree::
-   
+   :maxdepth: 1
+
    cast_dialog
    collation_dialog
    domain_dialog