Soong: Add synopsis to cc_prebuilt_* modules.

Added synopsis to the following modules under cc package:
    * cc_prebuilt_binary
    * cc_prebuilt_library_shared
    * cc_prebuilt_library_static

Bug: b/128337482
Test: Generated the documentation and verified that the synopsis was
added to each of the module.

Change-Id: I2ec284eb600f28d5c7f00254f441a3cc5fb684cc