[3.13] GH-133231: Backport PYTHON_JIT documentation to 3.13 (GH-133539)

Author: brandtbucher

.gitignore

@@ -138,7 +138,7 @@ Tools/unicode/data/
 # hendrikmuhs/ccache-action@v1
 /.ccache
 /cross-build/
-/jit_stencils.h
+/jit_stencils*.h
 /platform
 /profile-clean-stamp
 /profile-run-stamp

Doc/using/cmdline.rst

@@ -1229,6 +1229,14 @@ conflict.
 
    .. versionadded:: 3.13
 
+.. envvar:: PYTHON_JIT
+
+   On builds where experimental just-in-time compilation is available, this
+   variable can force the JIT to be disabled (``0``) or enabled (``1``) at
+   interpreter startup.
+
+   .. versionadded:: 3.13
+
 Debug-mode variables
 ~~~~~~~~~~~~~~~~~~~~
 

Doc/whatsnew/3.13.rst

@@ -390,11 +390,11 @@ without the optional value.
 
 * ``no``: Disable the entire Tier 2 and JIT pipeline.
 * ``yes``: Enable the JIT.
-  To disable the JIT at runtime, pass the environment variable ``PYTHON_JIT=0``.
+  To disable the JIT at runtime, pass the environment variable :envvar:`PYTHON_JIT=0 <PYTHON_JIT>`.
 * ``yes-off``: Build the JIT but disable it by default.
-  To enable the JIT at runtime, pass the environment variable ``PYTHON_JIT=1``.
+  To enable the JIT at runtime, pass the environment variable :envvar:`PYTHON_JIT=1 <PYTHON_JIT>`.
 * ``interpreter``: Enable the Tier 2 interpreter but disable the JIT.
-  The interpreter can be disabled by running with ``PYTHON_JIT=0``.
+  The interpreter can be disabled by running with :envvar:`PYTHON_JIT=0 <PYTHON_JIT>`.
 
 The internal architecture is roughly as follows: