fix(secret): Deduplicate based on rule ID and line range

[b40yd]

The same rule symfony-default-secret produced two SecretFinding instances on the same line 865. The deduplication key is RuleID:StartLine:EndLine:Offset. Since the two matches have different Offsets, they are not deduplicated. However, they are actually on the same line, and the code blocks are exactly identical, so users see duplicated output.

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[nikpivkin]

Hi @b40yd !

Could you please share an example that reproduces the issue?