Improve grammar description for the match statement #114172
Description
See #114070 (comment) by @hugovk. Right now we have here:
$ make -C Doc html SPHINXERRORHANDLING=-n SOURCES="reference/compound_stmts.rst"
Doc/reference/compound_stmts.rst:601: WARNING: 'token' reference target not found: python-grammar:star_named_expression
Doc/reference/compound_stmts.rst:601: WARNING: 'token' reference target not found: python-grammar:star_named_expressions
Doc/reference/compound_stmts.rst:601: WARNING: 'token' reference target not found: python-grammar:named_expression
Doc/reference/compound_stmts.rst:601: WARNING: 'token' reference target not found: python-grammar:block
Doc/reference/compound_stmts.rst:693: WARNING: 'token' reference target not found: python-grammar:named_expression
Doc/reference/compound_stmts.rst:835: WARNING: 'token' reference target not found: python-grammar:signed_number
Doc/reference/compound_stmts.rst:835: WARNING: 'token' reference target not found: python-grammar:signed_number
Doc/reference/compound_stmts.rst:835: WARNING: 'token' reference target not found: python-grammar:signed_number
Doc/reference/compound_stmts.rst:835: WARNING: 'token' reference target not found: python-grammar:strings
Doc/reference/compound_stmts.rst:835: WARNING: 'token' reference target not found: python-grammar:signed_number
Some rules are not clear without reading the full grammar specification. Perhaps, we can do better.