ext4: 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 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/20200706190339.20709-1-grandmaster@al2klimov.deSigned-off-by: Theodore Ts'o <tytso@mit.edu>

Documentation/filesystems/ext4/about.rst

@@ -39,6 +39,6 @@ entry.
 Other References
 ----------------
 
-Also see http://www.nongnu.org/ext2-doc/ for quite a collection of
+Also see https://www.nongnu.org/ext2-doc/ for quite a collection of
 information about ext2/3. Here's another old reference:
 http://wiki.osdev.org/Ext2

fs/ext4/Kconfig

@@ -110,7 +110,7 @@ config EXT4_KUNIT_TESTS
 	  This builds the ext4 KUnit tests.
 
 	  KUnit tests run during boot and output the results to the debug log
-	  in TAP format (http://testanything.org/). Only useful for kernel devs
+	  in TAP format (https://testanything.org/). Only useful for kernel devs
 	  running KUnit test harness and are not for inclusion into a production
 	  build.