Add lang + ref tags to frontmatter

Those are fields used by the language switcher to correlate pages across
different languages, even if they have different names/paths/titles.
They are generated with the prepare_for_translation.py script.

developer/debugging/automated-tests.md

@@ -1,9 +1,11 @@
 ---
+lang: en
 layout: doc
 permalink: /doc/automated-tests/
 redirect_from:
 - /en/doc/automated-tests/
 - /doc/AutomatedTests/
+ref: 45
 title: Automated Tests
 ---
 

developer/debugging/mount-lvm-image.md

@@ -1,6 +1,8 @@
 ---
+lang: en
 layout: doc
 permalink: /doc/mount-lvm-image/
+ref: 46
 title: Mount LVM image
 ---
 

developer/debugging/profiling.md

@@ -1,10 +1,12 @@
 ---
+lang: en
 layout: doc
 permalink: /doc/profiling/
 redirect_from:
 - /en/doc/profiling/
 - /doc/Profiling/
 - /wiki/Profiling/
+ref: 48
 title: Profiling
 ---
 

developer/debugging/safe-remote-ttys.md

@@ -1,8 +1,10 @@
 ---
+lang: en
 layout: doc
 permalink: /doc/safe-remote-ttys/
 redirect_from:
 - /en/doc/safe-remote-ttys/
+ref: 49
 title: Safe Remote Dom0 Terminals
 ---
 

developer/debugging/test-bench.md

@@ -1,10 +1,12 @@
 ---
+lang: en
 layout: doc
 permalink: /doc/test-bench/
 redirect_from:
 - /en/doc/test-bench/
 - /doc/TestBench/
 - /wiki/TestBench/
+ref: 44
 title: Test Bench
 ---
 

developer/debugging/vm-interface.md

@@ -1,4 +1,5 @@
 ---
+lang: en
 layout: doc
 permalink: /doc/vm-interface/
 redirect_from:
@@ -6,6 +7,7 @@ redirect_from:
 - /doc/VMInterface/
 - /doc/SystemDoc/VMInterface/
 - /wiki/SystemDoc/VMInterface/
+ref: 47
 title: VM Configuration Interface
 ---
 

developer/debugging/windows-debugging.md

@@ -1,10 +1,12 @@
 ---
+lang: en
 layout: doc
 permalink: /doc/windows-debugging/
 redirect_from:
 - /en/doc/windows-debugging/
 - /doc/WindowsDebugging/
 - /wiki/WindowsDebugging/
+ref: 50
 title: Windows Debugging
 ---