🐛 fix(xpath): allow an operator name after a * test

[gaborbernat]

xpath() rejected or, and, div and mod used as operators right after a * name test, and the expressions css_to_xpath emits for :has() tripped the same error, because the lexer always put the token after * in value position.
A * is a NameTest in value position and a MultiplyOperator in operator position per the XPath 1.0 lexical structure, so the token after a * NameTest is now an operator, and //* or 1, (* or 1) and descendant::* or descendant::p evaluate as lxml evaluates them.

//* or 1, (* or 1) and descendant::* or descendant::p now evaluate as they do in lxml, Saxon-HE 13 and elementpath. libxml2 parses div and mod only after a complete unary expression, and elementpath reads an operator name as a name only in prefix position.

closes #1039

[codspeed]

Merging this PR will improve performance by 6.11%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 2 improved benchmarks
✅ 579 untouched benchmarks
⏩ 32 skipped benchmarks¹

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	test_feature[select-relative-sibling]	45.6 µs	42.8 µs	+6.57%
⚡	test_feature[transform-number-count-last]	585.5 µs	554.2 µs	+5.64%

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing gaborbernat:fix/xpath-operator-after-star (ad8dd53) with main (48ae9ac)}

Footnotes

1. 32 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩