[docgen] Update docs

Author: github-actions

doc/orgmode.txt

@@ -1883,7 +1883,9 @@ The following highlight groups are used:
 *   `@org.headline.level7`: Headline at level 7 - linked to `Special`
 *   `@org.headline.level8`: Headline at level 8 - linked to `String`
 *   `@org.priority.highest`: Highest priority marker - linked to `@comment.error`
+*   `@org.priority.high`: High priority marker - Not linked to anything, defaults to normal text
 *   `@org.priority.default`: Default priority marker - Not linked to anything, defaults to normal text
+*   `@org.priority.low`: Lowest priority marker - Not linked to anything, defaults to normal text
 *   `@org.priority.lowest`: Lowest priority marker - Not linked to anything, defaults to normal text
 *   `@org.timestamp.active`: An active timestamp - linked to `@keyword`
 *   `@org.timestamp.inactive`: An inactive timestamp - linked to `@comment`