Fix unescaped "<" in MathML in PDF

[NSoiffer]

Link to issue number:

Fixes #18511

Summary of the issue:

If the structure tree is used for MathML in PDF, calls to getValue return the interpreted > so that it becomes < and we have an HTML syntax error.

Description of user facing changes:

The bug is fixed.

Description of developer facing changes:

None.

Description of development approach:

Called html.escape() for the result of the getValue (when it was not "none")

Testing strategy:

I used the pdf doc that was part of the issue and tested to make sure I saw the error before the fix and that there was no error after the fix.b

Known issues with pull request:

Code Review Checklist:

• Documentation:
  • Change log entry
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• x] API is compatible with existing add-ons.
• Security precautions taken.

@coderabbitai summary

[seanbudd]

This seems to have code changes from #18508

Could you clarify if that PR should be closed in favour of this one? There will be merge conflicts when we squash merge these.

[NSoiffer]

My apologies. I think I forgot to checkout master before creating the new branch. They are separate bugs, but both deal with PDF math and are in proximity to each other. Hence, they are slightly related. Please do whatever is simplest.

[seanbudd]

@NSoiffer - it would probably be better to remove the duplication to make it easier to track and revert the separate changes

[Copilot]

Pull Request Overview

This PR fixes an HTML syntax error in MathML PDF content where unescaped "<" characters were causing parsing issues. The fix ensures proper HTML escaping of values retrieved from PDF structure trees when generating MathML content.

• Added HTML escaping to node values in MathML generation
• Updated parameter passing for html.escape() to use explicit keyword argument

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
user_docs/en/changes.md	Added changelog entry documenting the MathML escaping fix
source/NVDAObjects/IAccessible/adobeAcrobat.py	Applied HTML escaping to PDF node values and updated parameter syntax

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