Fix mongoose docs generation

PUBLISHED_FROM=331821dcd1f7dc8a94581cd8a9b51aa00a89fddc

docs/c-api/mg_http.h/struct_mg_ssi_call_ctx.md

@@ -0,0 +1,14 @@
+---
+title: "struct mg_ssi_call_ctx"
+decl_name: "struct mg_ssi_call_ctx"
+symbol_kind: "struct"
+signature: |
+  struct mg_ssi_call_ctx {
+    struct http_message *req; /* The request being processed. */
+    struct mg_str file;       /* Filesystem path of the file being processed. */
+    struct mg_str arg; /* The argument passed to the tag: <!-- call arg -->. */
+  };
+---
+
+SSI call context 
+