bpo-33922: Adding documentation for new "-64" suffix of Python launcher (GH-7849)

Since bpo-30291 it is possible to specify the architecture of Python when using the launcher
diff --git a/Doc/using/windows.rst b/Doc/using/windows.rst
index 0165fff..2f3eb0e 100644
--- a/Doc/using/windows.rst
+++ b/Doc/using/windows.rst
@@ -154,7 +154,9 @@
 | DefaultJustForMeTargetDir | The default install directory for    | :file:`%LocalAppData%\\\ |
 |                           | just-for-me installs                 | Programs\\PythonXY` or   |
 |                           |                                      | :file:`%LocalAppData%\\\ |
-|                           |                                      | Programs\\PythonXY-32`   |
+|                           |                                      | Programs\\PythonXY-32` or|
+|                           |                                      | :file:`%LocalAppData%\\\ |
+|                           |                                      | Programs\\PythonXY-64`   |
 +---------------------------+--------------------------------------+--------------------------+
 | DefaultCustomTargetDir    | The default custom install directory | (empty)                  |
 |                           | displayed in the UI                  |                          |
@@ -762,9 +764,16 @@
 shebang lines starting with ``/usr``.
 
 Any of the above virtual commands can be suffixed with an explicit version
-(either just the major version, or the major and minor version) - for example
-``/usr/bin/python2.7`` - which will cause that specific version to be located
-and used.
+(either just the major version, or the major and minor version).
+Furthermore the 32-bit version can be requested by adding "-32" after the
+minor version. I.e. ``/usr/bin/python2.7-32`` will request usage of the
+32-bit python 2.7.
+
+.. versionadded:: 3.7
+
+   Beginning with python launcher 3.7 it is possible to request 64-bit version
+   by the "-64" suffix. Furthermore it is possible to specify a major and
+   architecture without minor (i.e. ``/usr/bin/python3-64``).
 
 The ``/usr/bin/env`` form of shebang line has one further special property.
 Before looking for installed Python interpreters, this form will search the
@@ -806,17 +815,18 @@
 In some cases, a version qualifier can be included in a command to dictate
 which version of Python will be used by the command. A version qualifier
 starts with a major version number and can optionally be followed by a period
-('.') and a minor version specifier. If the minor qualifier is specified, it
-may optionally be followed by "-32" to indicate the 32-bit implementation of
-that version be used.
+('.') and a minor version specifier. Furthermore it is possible to specifiy
+if a 32 or 64 bit implementation shall be requested by adding "-32" or "-64".
 
 For example, a shebang line of ``#!python`` has no version qualifier, while
 ``#!python3`` has a version qualifier which specifies only a major version.
 
-If no version qualifiers are found in a command, the environment variable
-``PY_PYTHON`` can be set to specify the default version qualifier - the default
-value is "2". Note this value could specify just a major version (e.g. "2") or
-a major.minor qualifier (e.g. "2.6"), or even major.minor-32.
+If no version qualifiers are found in a command, the environment
+variable :envvar:`PY_PYTHON` can be set to specify the default version
+qualifier. If it is not set, the default is "3". The variable can
+specify any value that may be passed on the command line, such as "3",
+"3.7", "3.7-32" or "3.7-64". (Note that the "-64" option is only
+available with the launcher included with Python 3.7 or newer.)
 
 If no minor version qualifiers are found, the environment variable
 ``PY_PYTHON{major}`` (where ``{major}`` is the current major version qualifier
@@ -834,8 +844,8 @@
 can be predicted knowing only what versions are installed on the PC and
 without regard to the order in which they were installed (i.e., without knowing
 whether a 32 or 64-bit version of Python and corresponding launcher was
-installed last). As noted above, an optional "-32" suffix can be used on a
-version specifier to change this behaviour.
+installed last). As noted above, an optional "-32" or "-64" suffix can be
+used on a version specifier to change this behaviour.
 
 Examples:
 
diff --git a/Misc/ACKS b/Misc/ACKS
index 19c7e43..5d7181d 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -723,6 +723,7 @@
 Gerhard Häring
 Fredrik Håård
 Florian Höch
+Robert Hölzl
 Catalin Iacob
 Mihai Ibanescu
 Ali Ikinci