import_style=typescript naming convention

I tried out `import_style=typescript` and found it has an issue with its file naming, in that it always capitalizes the first letter of the file path. When a proto file is in a subdirectory, e.g. `./foo/bar/service.proto`, the generated file is e.g., `./build/Foo/bar/serviceServiceClient.ts`.

It would probably be simple enough to fix the current logic to capitalize the basename rather than the full path, but I want to confirm whether this name mangling is even desired. There are many possible names for a proto file, and it seems difficult to come up with a scheme that doesn't have corner cases like the above `serviceServiceClient`. The `commonjs+dts` pattern of just appending `grpc_web` seems to have a better chance of a reasonably clean filename. Would it make sense to change `import_style=typescript` to have the same file naming as `commonjs+dts`?