Fix low surrogate false match in containsAny/containsNone/indexOfAny

[alhudz]

containsAny, containsNone and indexOfAny share one surrogate-aware guard that only special-cases a high surrogate.

1. when the matched char is a low surrogate the !isHighSurrogate(ch) term returns a match without checking the preceding high surrogate, so a low surrogate in the search set matches the low half of a different pair in the input.
2. StringUtils.containsAny("😀", "🨀".toCharArray()) is true and indexOfAny returns 1 although the inputs are U+1F600 and U+1FA00, distinct code points that only share the low surrogate \uDE00; index 1 also lands inside the pair, so slicing there yields malformed UTF-16.

Extended the guard so a low surrogate that is the trailing half of a pair in the search set only matches when the input carries the same high surrogate immediately before. Lone surrogates, BMP chars and matching pairs are unchanged.

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[Copilot]

Pull request overview

Fixes surrogate-aware matching in StringUtils.containsAny, containsNone, and indexOfAny to avoid false positives where a low surrogate in the search set could incorrectly match the low half of a different supplementary code point in the input (returning an index inside a surrogate pair).

Changes:

• Extend the surrogate guard logic to validate low-surrogate matches against the preceding high surrogate when the search set contains a surrogate pair.
• Add a supplementary fixture (U+24000) that shares a low surrogate with an existing fixture but has a different high surrogate.
• Add unit tests covering the “shared low surrogate, different code point” scenario for containsAny, containsNone, and indexOfAny.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
src/main/java/org/apache/commons/lang3/StringUtils.java	Tightens surrogate-pair matching so low surrogates from different code points don’t falsely match.
src/test/java/org/apache/commons/lang3/Supplementary.java	Adds CharU24000 fixture designed to share a low surrogate with CharU20000.
src/test/java/org/apache/commons/lang3/StringUtilsContainsTest.java	Adds regression tests for containsAny/containsNone with shared-low-surrogate supplementary chars.
src/test/java/org/apache/commons/lang3/StringUtilsEqualsIndexOfTest.java	Adds regression test ensuring indexOfAny does not return an index inside a surrogate pair for shared-low-surrogate cases.

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[garydgregory]

Thank you @alhudz , merged 🚀

[alhudz]

thanks for landing this one