Fix documentation typo.

Change-Id: I80083805a64665f46a6a4d85e1d9d52b1722264d
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/48025
Reviewed-by: Adam Langley <agl@google.com>

include/openssl/rsa.h

diff --git a/include/openssl/rsa.h b/include/openssl/rsa.h
index da7b2ff..27bc7bf 100644
--- a/include/openssl/rsa.h
+++ b/include/openssl/rsa.h
@@ -400,7 +400,7 @@
 // result for the signature scheme being implemented.
 //
 // WARNING: This function is a building block for a signature scheme, not a
-// complete one. Checking for arbitary strings in |out| will not result in a
+// complete one. Checking for arbitrary strings in |out| will not result in a
 // secure signature scheme.
 OPENSSL_EXPORT int RSA_verify_raw(RSA *rsa, size_t *out_len, uint8_t *out,
                                   size_t max_out, const uint8_t *in,