Add trailing slashes to request paths

[JoepdeJong]

I ran several search and replace commands:

Search	Replace	Example
Mapping\("([^"]+)"\)	Mapping({"$1","$1/"})	https://github.com/WISVCH/events/pull/485/files#diff-c3025750b3a87a6dfa05a796815873a57f7b4341765602218cc5e7b606c081f8R69
Mapping\(\)	Mapping({"","/"})	https://github.com/WISVCH/events/pull/485/files#diff-c3025750b3a87a6dfa05a796815873a57f7b4341765602218cc5e7b606c081f8L52
Mapping\(value = "([^"]+)"\)	Mapping({"$1","$1/"})	https://github.com/WISVCH/events/pull/485/files#diff-2761070d30b43c7a89f9b254d37bdbe030d39d6923254caf35b86f9e80363b35L40
Mapping\(value= "([^"]+)"\)	Mapping({"$1","$1/"})	https://github.com/WISVCH/events/pull/485/files#diff-2761070d30b43c7a89f9b254d37bdbe030d39d6923254caf35b86f9e80363b35L40
Mapping\(value = "([^"]+)"	Mapping(value = {"$1","$1/"}	https://github.com/WISVCH/events/pull/485/files#diff-db6dfb6e57023ba58bd2e8f6d842ec2a4643f03e4cafc6a211a7b8012587ae3aR34
Mapping\(""\)	Mapping({"","/"})	https://github.com/WISVCH/events/pull/485/files#diff-b9eb09e8eae6d4ed2faaf973720f36f305f612c6de3ba204f2fd066aa1540e8aR58

[JoepdeJong]

Closes #483