Remove deprecated add_axioms_from_bool method

[tautschnig]

Removed the deprecated add_axioms_from_bool(array_string_exprt, exprt) method and inlined its logic at the call site in string_format_builtin_function.cpp

Fixes: #8022

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• n/a The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.46%. Comparing base (6df204e) to head (af83392).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #8919      +/-   ##
===========================================
- Coverage    80.46%   80.46%   -0.01%     
===========================================
  Files         1704     1704              
  Lines       188665   188659       -6     
  Branches        73       73              
===========================================
- Hits        151805   151799       -6     
  Misses       36860    36860              

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[Copilot]

Pull request overview

This PR removes the deprecated string_constraint_generatort::add_axioms_from_bool(array_string_exprt, exprt) helper and inlines its (String.format-related) boolean formatting constraints directly at the call site, aligning with Issue #8022’s deprecation cleanup.

Changes:

• Removed the deprecated add_axioms_from_bool(const array_string_exprt &, const exprt &) declaration and definition.
• Inlined the "true" / "false" constraint generation into string_format_builtin_function.cpp for the BOOLEAN format specifier.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/solvers/strings/string_format_builtin_function.cpp	Inlines the boolean-to-string axioms previously implemented by the deprecated helper.
src/solvers/strings/string_constraint_generator.h	Removes the deprecated overload declaration from the generator interface.
src/solvers/strings/string_constraint_generator_valueof.cpp	Removes the deprecated overload implementation.

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