Apply suggestions from code review

Co-authored-by: Tom Cosgrove <tom.cosgrove@arm.com>
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 63649f4..ffc216e 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -2862,7 +2862,7 @@
 /**
  * \def MBEDTLS_PKCS7_C
  *
- * Enable PKCS7 core for using PKCS7 formatted signatures.
+ * Enable PKCS #7 core for using PKCS #7-formatted signatures.
  * RFC Link - https://tools.ietf.org/html/rfc2315
  *
  * Module:  library/pkcs7.c