Fix incorrect-modifier false positive on revert("msg") and custom-error reverts

[MarkLee131]

Summary

Fixes #3034:

incorrect-modifier was flagging modifiers ending in revert("msg") or revert MyError() as "does not always execute _; or revert."

Root Cause

is_revert in slither/detectors/functions/modifier.py:

def is_revert(node: Node) -> bool:
    return node.type == NodeType.THROW or any(
        ir.function.name in ["revert()", "revert(string"] for ir in node.internal_calls
    )

"revert(string" is missing the closing paren. The actual SolidityFunction.name for revert("msg") is "revert(string)" (see solidity_variables.py:55), so the membership check never matches.

Custom-error reverts are represented by SolidityCustomRevert with name = "revert " + signature. Also not in the kill set, so revert MyError() is missed too.

Fix

def is_revert(node: Node) -> bool:
    return node.type == NodeType.THROW or any(
        ir.function.name == "revert()"
        or ir.function.name == "revert(string)"
        or ir.function.name.startswith("revert ")  # SolidityCustomRevert
        for ir in node.internal_calls
    )

startswith("revert ") (trailing space) covers any SolidityCustomRevert.name, since they're all built as "revert " + signature.

Tests

Added tests/e2e/detectors/test_data/incorrect-modifier/0.8.20/modifier_revert_variants.sol. Covers revert(), revert("msg"), revert MyError(), revert MyError(args), plus one negative case that should still fire. After the fix only the negative case is reported.

The existing modifier_default.sol fixture (0.4.25 / 0.5.16 / 0.6.11 / 0.7.6) only uses bare revert(), which still matches exactly. Existing assertions unchanged.