Add conf.h to the documentation output

We don't want anyone using it, but we probably should render all our
documented headers. I've grouped it with the rest of the legacy X.509
stack.

Change-Id: If01dfd19c71598f47a40cd334b0fd7ef3e00685d
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/64928
Reviewed-by: Bob Beck <bbe@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
diff --git a/include/openssl/conf.h b/include/openssl/conf.h
index c9027c1..1e61326 100644
--- a/include/openssl/conf.h
+++ b/include/openssl/conf.h
@@ -67,7 +67,9 @@
 #endif
 
 
-// Config files look like:
+// Config files.
+//
+// This library handles OpenSSL's config files, which look like:
 //
 //   # Comment
 //
@@ -82,6 +84,7 @@
 // untrusted input as a config file risks string injection and denial of service
 // vulnerabilities.
 
+
 struct conf_value_st {
   char *section;
   char *name;
diff --git a/util/doc.config b/util/doc.config
index d6ae925..49b0ec6 100644
--- a/util/doc.config
+++ b/util/doc.config
@@ -56,6 +56,7 @@
     "Name": "Legacy ASN.1 and X.509 implementation (documentation in progress)",
     "Headers": [
       "include/openssl/asn1.h",
+      "include/openssl/conf.h",
       "include/openssl/time.h"
     ]
   },{