contrib: migrate off of a couple of bitbucket URLs

I noticed this when diffing the thg installer against Mercurial to see what was
missing.  There are a handful of other URLs in i18n and extension example help
text if anyone cares to update those.

Differential Revision: https://phab.mercurial-scm.org/D12606

contrib/packaging/wix/readme.rst

@@ -49,7 +49,7 b' Relationship to TortoiseHG'
 TortoiseHG uses the WiX files in this directory.
 
 The code for building TortoiseHG installers lives at
-https://bitbucket.org/tortoisehg/thg-winbuild and is maintained by
+https://foss.heptapod.net/mercurial/tortoisehg/thg-winbuild and is maintained by
 Steve Borho ([e-mail]).
 
 When changing behavior of the WiX installer, be sure to notify

contrib/win32/mercurial.ini

@@ -5,7 +5,7 b''
 ; This file will be replaced by the installer on every upgrade.
 ; Editing this file can cause strange side effects on Vista.
 ;
-; http://bitbucket.org/tortoisehg/stable/issue/135
+; https://foss.heptapod.net/mercurial/tortoisehg/thg/-/issues/135
 ;
 ; To change settings you see in this file, override (or enable) them in
 ; your user Mercurial.ini file, where USERNAME is your Windows user name: