removed unused variable , removed else block
added docblock comment
#6919 - add `SqlInterface#getSqlString()` return value signature
#6919 - fixed `Sql#getSqlStringForSqlObject()` return value
Merge branch 'cs/#6919-remove-unused-zend-db-sql-sql-variable'

Close #6919
Fix: Add missing return tag
Minor CS fix: docblock spacing
Merge branch 'cs/#6918-zend-di-runtimedefinition-hasprocessedclass-return-type'

Close #6918
Fix: Unnecessary FCQN
Merge branch 'cs/#6917-unnecessary-fqcn-removal'

Close #6917
Fix: Yet another unused local variable
Merge branch 'cs/#6916-remove-unused-db-variable-in-db2-select-decorator'

Close #6916
Fix: More unused local variables
Merge branch 'cs/#6915-zend-db-metadata-source-sqlite-metadata-unused-properties'

Close #6915
Fix: Remove unused parameter and class property
Merge branch 'cs/#6914-remove-oci8-driver-unused-parameters'

Close #6914
remove unnecessary variables
Merge branch 'cs/#6921-remove-unused-variable-assignments'

Close #6921