DATA: Update data files

Author: sev-

data/en/game_demos.yaml

@@ -13,7 +13,7 @@
     platform: dos
     '': ''
     category: ''
-    language: ''
+    language: en
     language2: ''
     language3: ''
     url: /frs/demos/access/martian-demo.zip

data/en/games.yaml

@@ -21,7 +21,7 @@
     year: '1991'
     moby_id: '222'
     steam_id: '302340'
-    gog_id: ''
+    gog_id: tex_murphy_1_2
     zoom_id: ''
     additional_stores: ''
     datafiles: Martian_Memorandum