Refactor Mongoose documentation

PUBLISHED_FROM=e9a4e5c7b4a1d03b93a2a79e29de19e60e919929

docs/c-api/http_server.h/mg_http_check_digest_auth.md

@@ -0,0 +1,12 @@
+---
+title: "mg_http_check_digest_auth()"
+decl_name: "mg_http_check_digest_auth"
+symbol_kind: "func"
+signature: |
+  int mg_http_check_digest_auth(struct http_message *hm, const char *auth_domain,
+                                FILE *fp);
+---
+
+Authenticates a HTTP request against an opened password file.
+Returns 1 if authenticated, 0 otherwise. 
+