Fix a typo in Swift codegen (#6470)
Fix a typo in Swift codegen (#6470)

* Fix a typo in Swift codegen

* Fix code formatting.
google/flatbuffers,alexames/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,google/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,google/flatbuffers,DavadDi/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,google/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,google/flatbuffers,google/flatbuffers,evolutional/flatbuffers,DavadDi/flatbuffers,google/flatbuffers,google/flatbuffers,alexames/flatbuffers,evolutional/flatbuffers,google/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,google/flatbuffers,google/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,DavadDi/flatbuffers,alexames/flatbuffers,google/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,google/flatbuffers,google/flatbuffers,evolutional/flatbuffers,DavadDi/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,DavadDi/flatbuffers,google/flatbuffers,DavadDi/flatbuffers,alexames/flatbuffers