[3.14] gh-151949: Fix Sphinx reference warnings in Doc/library/lzma.rst (GH-153878)

[miss-islington]

The lzma module constants (FORMAT_, CHECK_, PRESET_, FILTER_, MODE_*
and MF_*) were referenced with the :const: role throughout the module
documentation but were never defined as reference targets, producing
"reference target not found" warnings under nitpicky mode.

Document these public constants with .. data:: directives, following the
convention used by the signal, socket and ssl modules, so the existing
references resolve. The now-redundant inline descriptions of the format
and check constants are condensed into linked references.
(cherry picked from commit 1530b38)

Co-authored-by: Vyron Vasileiadis hi@fedonman.com

• Issue: Fix all Sphinx reference warnings in Doc/library/lzma.rst #151949

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #33708990 | 📁 Comparing 008afd9 against main (1530b38)

  🔍 Preview build  

414 files changed · + 1 added · ± 393 modified · - 20 deleted

+ Added

• library/asyncio-policy.html

± Modified

• about.html
• bugs.html
• glossary.html
• index.html
• license.html
• py-modindex.html
• c-api/allocation.html
• c-api/apiabiversion.html
• c-api/arg.html
• c-api/buffer.html
• and 383 more...

- Deleted

• _static/tachyon-example-flamegraph.html
• _static/tachyon-example-heatmap.html
• c-api/sentinel.html
• c-api/slots.html
• deprecations/c-api-pending-removal-in-3.19.html
• deprecations/c-api-pending-removal-in-3.20.html
• deprecations/pending-removal-in-3.20.html
• deprecations/pending-removal-in-3.21.html
• deprecations/soft-deprecations.html
• extending/first-extension-module.html
• and 10 more...

[fedonman]

The docs build fails here because this backport removes Doc/library/lzma.rst from Doc/tools/.nitignore, but six BCJ filter references in that file are still unresolved on this branch: FILTER_X86, FILTER_IA64, FILTER_ARM, FILTER_ARMTHUMB, FILTER_POWERPC and FILTER_SPARC.

On main those names carry a leading !, which tells Sphinx to render them as plain text and skip the reference lookup. That prefix came from GH-115989 (the ARM64 and RISCV filters), which was never backported, so this branch still has the plain references.

Adding the same ! prefix to those six lines clears the warnings. I don't have push access to this branch, so a core dev would need to apply it:

 * Branch-Call-Jump (BCJ) filters:

-  * :const:`FILTER_X86`
-  * :const:`FILTER_IA64`
-  * :const:`FILTER_ARM`
-  * :const:`FILTER_ARMTHUMB`
-  * :const:`FILTER_POWERPC`
-  * :const:`FILTER_SPARC`
+  * :const:`!FILTER_X86`
+  * :const:`!FILTER_IA64`
+  * :const:`!FILTER_ARM`
+  * :const:`!FILTER_ARMTHUMB`
+  * :const:`!FILTER_POWERPC`
+  * :const:`!FILTER_SPARC`

I checked with a nitpicky docs build that this clears all the lzma.rst warnings.