Merge pull request #418 from ngorskikh/feature/AG-29404

Update the `$permissions` modifier documentation

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

@@ -1954,10 +1954,12 @@ For the requests matching a `$permissions` rule, AdGuard strengthens response's
 
 **Syntax**
 
-`$permissions` value syntax is similar to the `Permissions-Policy` header [syntax](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Permissions-Policy) with one exception: comma that separates several features **MUST** be escaped.
-Pipe separator `|` instead of escaped comma is supported as well for better compatibility — see examples below.
+`$permissions` value syntax is identical to that of the `Permissions-Policy` header [syntax](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Permissions-Policy) with the following exceptions:
 
-The list of the available directives is available [here](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Permissions-Policy#directives).
+1. A comma that separates multiple features **MUST** be escaped — see examples below.
+2. A pipe character (`|`) can be used to separate features instead of a comma.
+
+The list of available directives is available [here](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Permissions-Policy#directives).
 
 `$permissions` value can be empty in the case of exception rules — see examples below.
 
@@ -1967,7 +1969,7 @@ The list of the available directives is available [here](https://developer.mozil
 - `@@||example.org/page/*$permissions=autoplay=()` disables all rules with the `$permissions` modifier exactly matching `autoplay=()` on all the pages matching the rule pattern. For instance, the rule above. It is important to note that the exception rule only takes effect in the case of an **exact value match**. For example, if you want to disable the rule  `$permissions=a=()\,b=()`, you need exception rule `@@$permissions=a=()\,b=()`, and **not** `@@$permissions=b=()\,a=()`, **nor** `@@$permissions=b=()` because `b=()\,a=()` or `b=()` does not match with `a=()\,b=()`.
 - `@@||example.org/page/*$permissions` disables all the `$permissions` rules on all the pages matching the rule pattern.
 - `$domain=example.org|example.com,permissions=storage-access=()\, camera=()` disallows using the Storage Access API to request access to unpartitioned cookies and using video input devices across `example.org` and `example.com`.
-- `||example.org^$permissions=storage-access=()|camera=()` — for better compatibility, we also support pipe-separated values for `$permissions` modifier.
+- `$domain=example.org|example.com,permissions=storage-access=()|camera=()` does the same — a `|` can be used to separate the features instead of an escaped comma.
 - `@@||example.org^$document` or `@@||example.org^$urlblock` disables all the `$permission` rules on all the pages matching the rule pattern.
 
 :::note
@@ -1992,8 +1994,9 @@ Firefox ignores the `Permissions-Policy` header. For more information, see [this
 
 :::caution Restrictions
 
-1. Characters forbidden in the `$permissions` value: `$`
-1. `$permissions` is compatible with three types of modifiers: `$domain`, `$important`, and `$subdocument`.
+1. Characters forbidden in the `$permissions` value: `$`.
+2. `$permissions` is compatible with a limited set of modifiers: `$domain`, `$important`, `$subdocument`, and [content-type modifiers](#content-type-modifiers).
+3. `$permissions` rules that do not have any [content-type modifiers](#content-type-modifiers) will match only requests where content type is `document`.
 
 :::