improve pattern and replacement args description

src/scriptlets/trusted-replace-xhr-response.js

@@ -26,15 +26,15 @@ import {
  *
  * **Syntax**
  * ```
- * example.org#%#//scriptlet('trusted-replace-xhr-response', pattern, replacement[, propsToMatch])
+ * example.org#%#//scriptlet('trusted-replace-xhr-response'[, pattern, replacement[, propsToMatch]])
  * ```
  *
-* - pattern - required, argument for matching contents of responseText that should be replaced.
+* - pattern - optional, argument for matching contents of responseText that should be replaced. If set, replacement is required.
  * Possible values:
  *   - string
  *   - regular expression
  *   - '*' to match all text content
- * - replacement - required, string to replace matched content with. Empty string to remove content.
+ * - replacement - optional, required, if pattern is set. String to replace matched content with. Empty string to remove content.
  * - propsToMatch — optional, string of space-separated properties to match for extra condition; possible props:
  *   - string or regular expression for matching the URL passed to `.open()` call;
  *   - colon-separated pairs name:value where