New release for eo-strings_0.4.0

[Graur]

New release for eo-strings_0.4.0

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PR-Codex overview

This PR focuses on updating the version of the org.eolang.txt package and its dependencies. It also adds new functionality and fixes some issues.

Detailed summary

• Updated the version of the org.eolang.txt package and its dependencies to 0.4.0
• Added new objects and tests for string manipulation
• Added support for regular expressions in the org.eolang.txt package
• Improved the trimming and splitting functionality of strings
• Added new methods to check if a string contains alphabetic or ASCII characters
• Added new method to repeat a string multiple times

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