docs/lib: fix typos

Repated 'the the' and 'with with'

Closes #20933

docs/FAQ.md

@@ -248,7 +248,7 @@ An incomprehensible description of the two numbers above is available on
 We strongly encourage you to submit changes and improvements directly as [pull
 requests on GitHub](https://github.com/curl/curl/pulls).
 
-If you cannot or choose not to engage with with GitHub, send your patch
+If you cannot or choose not to engage with GitHub, send your patch
 to the curl-library mailing list. We are many subscribers there and there are
 lots of people who can review patches, comment on them and receive them
 properly.

lib/cfilters.c

@@ -1033,7 +1033,7 @@ size_t Curl_conn_get_max_concurrent(struct Curl_easy *data,
   result = cf ? cf->cft->query(cf, data, CF_QUERY_MAX_CONCURRENT,
                                &n, NULL) : CURLE_UNKNOWN_OPTION;
   /* If no filter answered the query, the default is a non-multiplexed
-   * connection with limit 1. Otherwise, the the query may return 0
+   * connection with limit 1. Otherwise, the query may return 0
    * for connections that are in shutdown, e.g. server HTTP/2 GOAWAY. */
   return (result || n < 0) ? 1 : (size_t)n;
 }

lib/doh.c

@@ -205,7 +205,7 @@ static void doh_print_buf(struct Curl_easy *data,
 #endif
 
 /* called from multi when a sub transfer, e.g. doh probe, is done.
- * This looks up the the probe response at its meta CURL_EZM_DOH_PROBE
+ * This looks up the probe response at its meta CURL_EZM_DOH_PROBE
  * and copies the response body over to the struct at the master's
  * meta at CURL_EZM_DOH_MASTER. */
 static void doh_probe_done(struct Curl_easy *data,