tty: vt: Replace HTTP links with HTTPS ones

Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  If not .svg:
    For each line:
      If doesn't contain `\bxmlns\b`:
        For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
	  If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`:
            If both the HTTP and HTTPS versions
            return 200 OK and serve the same content:
              Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200718133452.24290-1-grandmaster@al2klimov.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/driver-api/serial/n_gsm.rst

@@ -5,7 +5,7 @@ GSM 0710 tty multiplexor HOWTO
 This line discipline implements the GSM 07.10 multiplexing protocol
 detailed in the following 3GPP document:
 
-	http://www.3gpp.org/ftp/Specs/archive/07_series/07.10/0710-720.zip
+	https://www.3gpp.org/ftp/Specs/archive/07_series/07.10/0710-720.zip
 
 This document give some hints on how to use this driver with GPRS and 3G
 modems connected to a physical serial port.

drivers/tty/vt/vt.c

@@ -2520,7 +2520,7 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 
 /* is_double_width() is based on the wcwidth() implementation by
  * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
- * Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
+ * Latest version: https://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
  */
 struct interval {
 	uint32_t first;