Update mg_get_http_header.md

docs/c-api/http.h/mg_get_http_header.md

@@ -6,7 +6,7 @@ signature: |
   struct mg_str *mg_get_http_header(struct http_message *hm, const char *name);
 ---
 
-Search and return header `name` in parsed HTTP message `hm`.
+Searches and returns the header `name` in parsed HTTP message `hm`.
 If header is not found, NULL is returned. Example:
 
     struct mg_str *host_hdr = mg_get_http_header(hm, "Host");