[TypeDeclaration] Add BoolReturnTypeFromBooleanConstAndStrictReturnsRector for mixed const + strict bool returns

[TomasVotruba]

Adds return type : bool to methods that mix direct true/false const returns with strict bool expression returns - a case that fell between two existing rules.

The gap

public function checkContext(array|string $context)
{
    if (empty($this->context)) {
        return true;                    // const bool
    }

    return 0 === stripos(/* ... */);    // strict bool expr
}

• BoolReturnTypeFromBooleanConstReturnsRector fires only when all returns are true/false const.
• BoolReturnTypeFromBooleanStrictReturnsRector fires only when all returns are strict bool expressions.

A method mixing both kinds matched neither, so no : bool was added.

This rule

Fires only when every return is bool and at least one is a const while at least one is a strict expression. Pure-const and pure-strict stay owned by the existing rules, so the three rules are disjoint and idempotent on each other's output.

Registered in TypeDeclarationLevel right after the strict-returns rule.