Fix incorrect type hint in TableDiff
Fix incorrect reference to PDO in DB2Statement
Don't return the return values of methods that do not return anything
Add missing @param tags
Merge pull request #583 from JeroenDeDauw/tablediff

Fix incorrect type hint in TableDiff
Merge pull request #585 from JeroenDeDauw/DB2Statement

Fix incorrect reference to PDO in DB2Statement
Merge pull request #588 from JeroenDeDauw/void

Don't return the return values of methods that do not return anything
Merge pull request #589 from JeroenDeDauw/param

Add missing @param tags