Docs: Generic update to the eRPC framework document

- Update obsolete information,
- Basic RST style fixes found by doc8,
- Add command example to generate shim code.

Signed-off-by: David Vincze <david.vincze@arm.com>
Change-Id: If59a7bc259b511f69a4ecd029cdd8b4f272c1d98
3 files changed