Remove redundant PHPDoc blocks that are identical to the code

Thanks to strict types and a recent MediaWiki CodeSniffer update a
lot of the PHPDoc comments in this codebase became redundant. Only
very few comments in this codebase contain additional information.
Such comments don't add any new information to what the code alone
already says. We started removing them in many other codebases
already.

In case someone wants to add more documentation to a method the
basic PHPDoc block can usually automatically be generated with a
button press in the IDE.

The only additional change in this patch is that I occasionally
add a missing `void` return type. This is necessary to be able to
remove the comment.

Change-Id: Id7d6d6a437175a9d017f564daf7ed16e76f09158

src/Parsoid/Poem.php

@@ -31,9 +31,6 @@ public function getConfig(): array {
 		];
 	}
 
-	/**
-	 * @param ?ParsoidExtensionAPI $extApi
-	 */
 	public function __construct( ?ParsoidExtensionAPI $extApi = null ) {
 		/* @phan-suppress-previous-line PhanEmptyPublicMethod */
 		/* The dom post processor doesn't need to use $extApi, so ignore it */

src/Parsoid/PoemProcessor.php

@@ -32,9 +32,6 @@ public function wtPostprocess(
 		}
 	}
 
-	/**
-	 * @param Element $node
-	 */
 	private function processNowikis( Element $node ): void {
 		$doc = $node->ownerDocument;
 		$c = $node->firstChild;