Rename *KEYPAIR* to *KEY_PAIR*

Be consistent with PUBLIC_KEY.

perl -i -pe 's/KEYPAIR/KEY_PAIR/g' $(git ls-files)
diff --git a/docs/getting_started.md b/docs/getting_started.md
index 9a702ea..ac1bc31 100644
--- a/docs/getting_started.md
+++ b/docs/getting_started.md
@@ -73,7 +73,7 @@
 1. Test the information stored in this slot:
 ```C
     int key_slot = 1;
-    uint8_t *data = "KEYPAIR_KEY_DATA";
+    uint8_t *data = "KEY_PAIR_KEY_DATA";
     size_t data_size;
     psa_key_type_t type = PSA_KEY_TYPE_RSA_PUBLIC_KEY;
     size_t got_bits;
@@ -127,7 +127,7 @@
                              PSA_ALG_RSA_PKCS1V15_SIGN_RAW);
     status = psa_set_key_policy(key_slot, &policy);
 
-    status = psa_import_key(key_slot, PSA_KEY_TYPE_RSA_KEYPAIR,
+    status = psa_import_key(key_slot, PSA_KEY_TYPE_RSA_KEY_PAIR,
                             key, sizeof(key));
 
     /* Sing message using the key */