docs: locking: 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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200713115728.33905-1-grandmaster@al2klimov.de

Documentation/locking/mutex-design.rst

@@ -18,7 +18,7 @@ as an alternative to these. This new data structure provided a number
 of advantages, including simpler interfaces, and at that time smaller
 code (see Disadvantages).
 
-[1] http://lwn.net/Articles/164802/
+[1] https://lwn.net/Articles/164802/
 
 Implementation
 --------------