🐛 fix(markdown): keep edge spaces in inline code

[gaborbernat]

to_markdown wrote inline code that starts and ends with a space as written. <p>x<code> a </code>y</p> became x` a `y, and a reader strips one space from each end of such content (CommonMark 6.1), so it read back as xay in one word.

Content that both starts and ends with a space, and is not all spaces, now gets one more space on each side, as content edged by a backtick already did. The example becomes x` a `y.

markdownify 1.2.3 writes x `a` y, moving the spaces outside the code, and html2text 2025.4.15 writes x` a `y, which loses them.

[codspeed]

Merging this PR will regress 1 benchmark

⚠️ 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

⚡ 1 improved benchmark
❌ 1 regressed benchmark
✅ 579 untouched benchmarks
⏩ 32 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	test_feature[prune-shared-single]	89.1 µs	96.7 µs	-7.83%
⚡	test_feature[shadow-slot-comments]	137.9 µs	110.1 µs	+25.23%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing gaborbernat:fix/markdown-code-span-spaces (7d4e4e0) with main (af31f20)}

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. ↩