Reverse the sentinel logic and include the debug message only if sentinel=true. This way it must be explicitly set and avoids breaking the html-comment-wrapped sentinel message within html-comments and html-attributes.

Ref: syslabcom/oira.prototype#559

Author: thet

i18n

@@ -1,4 +1,4 @@
-{%- unless include.sentinel == false -%}<!-- i18n: {{ include.id }} -->{%- endunless -%}
+{%- if include.sentinel == true -%}<!-- i18n: {{ include.id }} -->{%- endif -%}
 {%- if page.lang -%}
     {%- assign this_lang = page.lang -%}
 {%- else -%}
@@ -27,4 +27,4 @@
     {{- site.data[ui_data_path].ui[this_id]['en'] -}}
 {%- else -%}
     {{- site.data[ui_data_path].ui[this_id][this_lang] -}}
-{%- endif -%}
+{%- endif -%}