getrandom_crypto.c: Add function to the documentation

Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
(cherry picked from commit d57a383d43)

src/getrandom_crypto.c

@@ -24,6 +24,12 @@
 #include "libssh/crypto.h"
 #include <openssl/rand.h>
 
+/**
+ * @addtogroup libssh_misc
+ *
+ * @{
+ */
+
 /**
  * @brief Get random bytes
  *
@@ -52,3 +58,7 @@ ssh_get_random(void *where, int len, int strong)
     /* Returns -1 when not supported, 0 on error, 1 on success */
     return !!RAND_bytes(where, len);
 }
+
+/**
+ * @}
+ */