Add new rule for detecting some unescaped dots

If an unescaped dot (`.`) is found in a regex pattern, and it can be reasonably determined that the dot is still part of a valid domain or is followed by a valid TLD, a warning should be displayed, suggesting that the dot should be escaped.

For example, the following rules:

```adblock
/example.ru\/uploads\/banner\d+.png/
/example.(com|org)/
```
Should be rewritten as:

```adblock
/example\.ru\/uploads\/banner\d+.png/
/example\.(com|org)/
```

This is because an **unescaped dot (`.`)** in a regex pattern represents **any character**, while an **escaped dot (`\.`)** explicitly represents a **literal dot (`.`)**.

Can be autofixed.