Align remaining TLS ECDH APIs on "group" terminology

This adds "group" versions of our codepoint-based APIs. This is mostly
because it looks weird to switch terminology randomly in the
implementation. See I7a356793d36419fc668364c912ca7b4f5c6c23a2 for
additional context.

I've not bothered renaming the bssl_shim flags. That seems a waste of
time.

Change-Id: I566ad132f5a33d99efd8cb2bb8b76d9a6038c825
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/60207
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
diff --git a/ssl/extensions.cc b/ssl/extensions.cc
index 974a36c..c5b1ed1 100644
--- a/ssl/extensions.cc
+++ b/ssl/extensions.cc
@@ -206,7 +206,7 @@
 
 static bool is_post_quantum_group(uint16_t id) {
   switch (id) {
-    case SSL_CURVE_X25519_KYBER768_DRAFT00:
+    case SSL_GROUP_X25519_KYBER768_DRAFT00:
       return true;
     default:
       return false;
@@ -307,9 +307,9 @@
 }
 
 static const uint16_t kDefaultGroups[] = {
-    SSL_CURVE_X25519,
-    SSL_CURVE_SECP256R1,
-    SSL_CURVE_SECP384R1,
+    SSL_GROUP_X25519,
+    SSL_GROUP_SECP256R1,
+    SSL_GROUP_SECP384R1,
 };
 
 Span<const uint16_t> tls1_get_grouplist(const SSL_HANDSHAKE *hs) {