[AG-31991] Remove complicated heuristics for $domain modifier

Now that we have the `$to` modifier, `$domain` will no longer match the target domain
by default - only when the `$csp` or `$cookie` modifiers are specified.

See-also: AG-31991
Signed-off-by: Alexey Zhavoronkov <[email protected]>

Author: workingBanana

docs/general/ad-filtering/create-own-filters.md

@@ -537,34 +537,21 @@ If you want the rule not to be applied to certain domains, start a domain name w
 
 **`$domain` modifier matching target domain:**
 
-In some cases the `$domain` modifier can match not only the referrer domain, but also the target domain. This happens when all the following conditions are met:
+In some cases the `$domain` modifier can match not only the referrer domain, but also the target domain.
 
-1. The request has the `document` content type
-1. The rule pattern does not match any particular domains
-1. The rule pattern does not contain regular expressions
-1. The `$domain` modifier contains only excluded domains, e.g. `$domain=~example.org|~example.com`
-
-The following predicate should be satisfied to perform a target domain matching:
-
-```text
-1 AND ((2 AND 3) OR 4)
-```
-
-That is, if the modifier `$domain` contains only excluded domains, then the rule does not need to meet the second and third conditions to match the target domain against the modifier `$domain`.
-
-If some of the conditions above are not met but the rule contains [`$cookie`](#cookie-modifier) or [`$csp`](#csp-modifier) modifier, the target domain will still be matched.
+If the rule contains [`$cookie`](#cookie-modifier) or [`$csp`](#csp-modifier) modifier, the target domain will be matched.
 
 If the referrer matches a rule with `$domain` that explicitly excludes the referrer domain, then the rule will not be applied even if the target domain also matches the rule. This affects rules with [`$cookie`](#cookie-modifier) and [`$csp`](#csp-modifier) modifiers, too.
 
 **Examples**
 
 - `*$cookie,domain=example.org|example.com` will block cookies for all requests to and from `example.org` and `example.com`.
-- `*$document,domain=example.org|example.com` will block all requests to and from `example.org` and `example.com`.
+- `*$document,domain=example.org|example.com` will block all requests from `example.org` and `example.com` but not to them.
 
 In the following examples it is implied that requests are sent from `http://example.org/page` (the referrer) and the target URL is `http://targetdomain.com/page`.
 
 - `page$domain=example.org` will be matched, as it matches the referrer domain.
-- `page$domain=targetdomain.com` will be matched, as it matches the target domain and satisfies all requirements mentioned above.
+- `page$domain=targetdomain.com` will not be matched, as it matches the target domain but rule doesn't contain `$cookie` or `$csp` modifiers.
 - `||*page$domain=targetdomain.com` will not be matched, as the pattern `||*page` may match specific domains,
 e.g. `example.page`.
 - `||*page$domain=targetdomain.com,cookie` will be matched because the rule contains `$cookie` modifier