In code, structs that happened to have a '(' somewhere in their body
would cause the parser to go wrong. This change fixes that and updates
the comments on a number of structs.
Change-Id: Ia76ead266615a3d5875b64a0857a0177fec2bd00
Reviewed-on: https://boringssl-review.googlesource.com/6970
Reviewed-by: Adam Langley <agl@google.com>