RT4593: Add space after comma (doc nits)

Update find-doc-nits to find errors in SYNOPSIS (the most common
place where they were missing).

Reviewed-by: Matt Caswell <matt@openssl.org>
diff --git a/doc/crypto/RSA_generate_key.pod b/doc/crypto/RSA_generate_key.pod
index a8fab52..3bafc6f 100644
--- a/doc/crypto/RSA_generate_key.pod
+++ b/doc/crypto/RSA_generate_key.pod
@@ -14,7 +14,7 @@
 
  #if OPENSSL_API_COMPAT < 0x00908000L
  RSA *RSA_generate_key(int num, unsigned long e,
-    void (*callback)(int,int,void *), void *cb_arg);
+    void (*callback)(int, int, void *), void *cb_arg);
  #endif
 
 =head1 DESCRIPTION