fix bugs: stabilize htmlContent by normalizing tableRows whitespace/boundary events

[chihyu0917]

Motivation

MarkdownParserTest#testHtmlContent was brittle around HTML tables.
Inside <table><tbody>…</tbody></table>, the event stream intermittently included extra "text" whitespace nodes and "unknown" nodes (tbody boundary markers), which caused order-sensitive assertions to fail (e.g., expecting text but seeing tableRow / tableHeaderCell_). This is environmental/renderer dependent and shows up under different JDKs/runners and with NonDex.

Design / Implementation

• Replace the large positional assertSinkEquals(...) block for this test with a compact normalization loop:
  • Iterate the emitted events.
  • Track when we are inside tableRows … tableRows_.
  • While inside that region, skip intermittent "text" and "unknown" events.
  • Compare the remaining sequence with a concise exp list.
    Scope is only htmlContent; no production code touched, no new imports or dependencies.

Reproduce the error

• Error message: org.apache.maven.doxia.module.markdown.MarkdownParserTest.htmlContent -- Time elapsed: 0.869 s <<< FAILURE! org.opentest4j.AssertionFailedError
• Reproduce: mvn -pl doxia-modules/doxia-module-markdown edu.illinois:nondex-maven-plugin:2.1.7:nondex -Dtest=org.apache.maven.doxia.module.markdown.MarkdownParserTest#htmlContent

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[chihyu0917]

I rerun mvn spotless:apply to ensure not failing in CI