editcap: Fixup our help output.

Make sure list_capture_types prints to the designated stream so that
tools/update-tools-help.py works correctly for `editcap -F`.

docbook/wsug_src/editcap-F.txt

@@ -1 +1,37 @@
 editcap: The available capture file types for the "-F" flag are:
+    pcap - Wireshark/tcpdump/... - pcap
+    pcapng - Wireshark/... - pcapng
+    5views - InfoVista 5View capture
+    btsnoop - Symbian OS btsnoop
+    commview - TamoSoft CommView
+    dct2000 - Catapult DCT2000 trace (.out format)
+    eyesdn - EyeSDN USB S0/E1 ISDN trace format
+    k12text - K12 text file
+    lanalyzer - Novell LANalyzer
+    logcat - Android Logcat Binary format
+    logcat-brief - Android Logcat Brief text format
+    logcat-long - Android Logcat Long text format
+    logcat-process - Android Logcat Process text format
+    logcat-tag - Android Logcat Tag text format
+    logcat-thread - Android Logcat Thread text format
+    logcat-threadtime - Android Logcat Threadtime text format
+    logcat-time - Android Logcat Time text format
+    modpcap - Modified tcpdump - pcap
+    netmon1 - Microsoft NetMon 1.x
+    netmon2 - Microsoft NetMon 2.x
+    nettl - HP-UX nettl trace
+    ngsniffer - Sniffer (DOS)
+    ngwsniffer_1_1 - NetXray, Sniffer (Windows) 1.1
+    ngwsniffer_2_0 - Sniffer (Windows) 2.00x
+    niobserver - Network Instruments Observer
+    nokiapcap - Nokia tcpdump - pcap
+    nsecpcap - Wireshark/tcpdump/... - nanosecond pcap
+    nstrace10 - NetScaler Trace (Version 1.0)
+    nstrace20 - NetScaler Trace (Version 2.0)
+    nstrace30 - NetScaler Trace (Version 3.0)
+    nstrace35 - NetScaler Trace (Version 3.5)
+    rf5 - Tektronix K12xx 32-bit .rf5 format
+    rh6_1pcap - RedHat 6.1 tcpdump - pcap
+    snoop - Sun snoop
+    suse6_3pcap - SuSE 6.3 tcpdump - pcap
+    visual - Visual Networks traffic capture

editcap.c

@@ -894,7 +894,7 @@ list_capture_types(FILE *stream) {
     writable_type_subtypes = wtap_get_writable_file_types_subtypes(FT_SORT_BY_NAME);
     for (guint i = 0; i < writable_type_subtypes->len; i++) {
         int ft = g_array_index(writable_type_subtypes, int, i);
-        fprintf(stderr, "    %s - %s\n", wtap_file_type_subtype_name(ft),
+        fprintf(stream, "    %s - %s\n", wtap_file_type_subtype_name(ft),
                 wtap_file_type_subtype_description(ft));
     }
     g_array_free(writable_type_subtypes, TRUE);