Unreachable Code warning for abstract contract

## Description

When an abstract contract function calls a pure virtual function, and a concrete implementation of that function (in a concrete contracts) reverts, the `Warning: Unreachable code.` is shown which is incorrect/misleading.

## Environment

- Compiler version: commit https://github.com/ethereum/solidity/commit/a1b79de64235f13e6b06e088fe6365c5a12d13d3

## Steps to Reproduce

```solidity
pragma solidity ^0.8.20;
// SPDX-License-Identifier: AGPL-3.0-or-later

abstract contract AbstractContract {
bool public abstractCalled;
error Unimplemented();

function outer() external {
inner();

abstractCalled = true;
}

function inner() internal virtual;
}

contract ChildContract1 is AbstractContract {
bool public wasCalled;

function inner() internal override {
wasCalled = true;
}
}

contract ChildContract2 is AbstractContract {

function inner() internal pure override {
revert Unimplemented();
}
}
```

Gives the error:
```
Warning: Unreachable code.
--> contracts/6_unreachable.sol:11:9:
|
11 | abstractCalled = true;
| ^^^^^^^^^^^^^^^^^^^^^
```

However when `ChildContract1.outer()` is called, the `wasCalled` is correctly set to true. The warning is misleading.

Start by compiling the Solidity reproduction in contracts/6_unreachable.sol with the referenced compiler commit and inspect the unreachable-code diagnostic at line 11. Compare behavior for ChildContract1 and ChildContract2; done means the valid ChildContract1 path no longer receives a misleading warning while the reverting case remains correctly handled.

Written by the indexing model from the issue text.