Kotlin: drop "/JVM" from Kotlin language page title

[chalin]

Now that grpc.io has a Platforms section, I'd like to propose (for sake of uniformity with other languages, including Dart, that can target different platforms) that we drop the "/JVM" qualifier from the Kotlin language landing page.

Thoughts @lowasser @bshaffer @davidwiner @jamesward?

Original context that gave rise to the introduction of "/JVM": #132 (comment)

@lowasser commented on Mar 17
It might be worth marking it as "Kotlin/JVM" rather than "Kotlin" generically, though? We are not yet supporting the Javascript or Native compilation backends for Kotlin.

[jamesward]

Sounds good to me!