pw_rpc: Rename ServerCall to CallContext

The ServerCall object will be used for both the server and client, so
rename it to "CallContext".

Change-Id: I360f923e1d322ff4c8ee3876e7c51fcfcf6f6dc3
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/59486
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Alexei Frolov <frolv@google.com>
diff --git a/pw_rpc/responder.cc b/pw_rpc/responder.cc
index fadf2c9..896799d 100644
--- a/pw_rpc/responder.cc
+++ b/pw_rpc/responder.cc
@@ -22,7 +22,7 @@
 namespace pw::rpc::internal {
 namespace {
 
-Packet ResponsePacket(const ServerCall& call,
+Packet ResponsePacket(const CallContext& call,
                       std::span<const std::byte> payload,
                       Status status) {
   return Packet(PacketType::RESPONSE,
@@ -33,7 +33,7 @@
                 status);
 }
 
-Packet StreamPacket(const ServerCall& call,
+Packet StreamPacket(const CallContext& call,
                     std::span<const std::byte> payload) {
   return Packet(PacketType::SERVER_STREAM,
                 call.channel().id(),
@@ -44,7 +44,7 @@
 
 }  // namespace
 
-Responder::Responder(const ServerCall& call, MethodType type)
+Responder::Responder(const CallContext& call, MethodType type)
     : call_(call),
       rpc_state_(kOpen),
       type_(type),