Fix spelling and typographical errors found by cspell

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/include/mbedtls/aria.h b/include/mbedtls/aria.h
index 6e47272..d294c47 100644
--- a/include/mbedtls/aria.h
+++ b/include/mbedtls/aria.h
@@ -321,7 +321,7 @@
  *             for example, with 96-bit random nonces, you should not encrypt
  *             more than 2**32 messages with the same key.
  *
- *             Note that for both stategies, sizes are measured in blocks and
+ *             Note that for both strategies, sizes are measured in blocks and
  *             that an ARIA block is 16 bytes.
  *
  * \warning    Upon return, \p stream_block contains sensitive data. Its