doc/man3: use the documented coding style in the example code

Adjust brace placement, whitespace after keywords, indentation and empty
lines after variable declarations according to
https://www.openssl.org/policies/codingstyle.html.

Indent literal sections by exactly one space.
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3580)

doc/man3/ASN1_TIME_set.pod

@@ -109,6 +109,7 @@ Determine if one time is later or sooner than the current time:
 
  if (!ASN1_TIME_diff(&day, &sec, NULL, to))
      /* Invalid time format */
+
  if (day > 0 || sec > 0)
      printf("Later\n");
  else if (day < 0 || sec < 0)

doc/man3/SSL_CTX_set_tmp_dh_callback.pod

@@ -93,6 +93,7 @@ Command-line parameter generation:
 Code for setting up parameters during server initialization:
 
  SSL_CTX ctx = SSL_CTX_new();
+
  DH *dh_2048 = NULL;
  FILE *paramfile = fopen("dh_param_2048.pem", "r");