Delete "About QL" and references to it

Author: Shati Patel

docs/language/learn-ql/about-ql.rst

@@ -19,7 +19,6 @@ CodeQL is based on a powerful query language called QL. The following topics hel
    :maxdepth: 1
 
    introduction-to-ql
-   about-ql
    beginner/ql-tutorials
    writing-queries/writing-queries
    cpp/ql-for-cpp

docs/language/learn-ql/index.rst

@@ -165,4 +165,4 @@ Learning CodeQL
 
 -  To find out more about how to write your own queries, try working through the :doc:`QL tutorials <beginner/ql-tutorials>`.
 -  For an overview of the other available resources, see :doc:`Learning CodeQL <../index>`.
--  For a more technical description of the underlying language, see :doc:`About QL <about-ql>`.
+-  For a more technical description of the underlying language, see the `QL language reference <https://help.semmle.com/QL/ql-handbook>`__

docs/language/learn-ql/introduction-to-ql.rst

@@ -124,7 +124,7 @@ QL is:
 
 .. note::
 
-  QL is the high-level, object-oriented logic language that underpins all CodeQL libraries and analyses. You can learn lots more about QL by visiting `Introduction to the QL language <https://help.semmle.com/QL/learn-ql/ql/introduction-to-ql.html>`__ and `About QL <https://help.semmle.com/QL/learn-ql/ql/about-ql.html>`__.
+  QL is the high-level, object-oriented logic language that underpins all CodeQL libraries and analyses. You can learn lots more about QL by visiting the `QL language reference <https://help.semmle.com/QL/ql-handbook>`__.
   The key features of QL are:
 
   - All common logic connectives are available, including quantifiers like ``exist``, which can also introduce new variables.