pw_rpc: Rename base_server_writer files

This file rename was done in a separate change from the class rename so
Git would detect these as file moves rather than new files.

Change-Id: I37b6168b142197628b6694736ce0fbe36e44b263
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/49201
Commit-Queue: Wyatt Hepler <hepler@google.com>
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
Reviewed-by: Alexei Frolov <frolv@google.com>
diff --git a/pw_rpc/BUILD.gn b/pw_rpc/BUILD.gn
index bc82b77..a1efb04 100644
--- a/pw_rpc/BUILD.gn
+++ b/pw_rpc/BUILD.gn
@@ -54,14 +54,14 @@
     "public/pw_rpc/service.h",
   ]
   sources = [
-    "base_server_writer.cc",
-    "public/pw_rpc/internal/base_server_writer.h",
     "public/pw_rpc/internal/call.h",
     "public/pw_rpc/internal/hash.h",
     "public/pw_rpc/internal/method.h",
     "public/pw_rpc/internal/method_lookup.h",
     "public/pw_rpc/internal/method_union.h",
+    "public/pw_rpc/internal/responder.h",
     "public/pw_rpc/internal/server.h",
+    "responder.cc",
     "server.cc",
     "service.cc",
   ]
@@ -217,7 +217,7 @@
     ":server",
     ":test_utils",
   ]
-  sources = [ "base_server_writer_test.cc" ]
+  sources = [ "responder_test.cc" ]
 }
 
 pw_test("channel_test") {