remove &$var reference notations in phpdoc

this isn't required by the spec and PHPStan chokes on it. I was previously having it ignore these errors, but it turns out that PHPStan is not making use of extended typeinfo provided if it can't parse the tag, which is problematic on level 6 and also a problem for array-of-type. Therefore, we are going to have to take the hit.

tests/phpstan/configs/phpstan-bugs.neon

@@ -1,9 +1,5 @@
 parameters:
 	ignoreErrors:
-		-
-			message: "#^PHPDoc tag @param has invalid value \\(.+\\)\\: Unexpected token \"&\", expected variable at offset \\d+$#"
-			path: ../../../src
-
 		-
 			message: "#^Default value of the parameter \\#\\d+ \\$[A-Za-z\\d_]+ \\(\\-?\\d+\\) of method .+\\(\\) is incompatible with type float\\.$#"
 			path: ../../../src