fix: do not link raw text object

Author: oesteban

docs/assets/ORN-Workshop/index.html

@@ -259,7 +259,7 @@
           highlightLines: true,
           countIncrementalSlides: false,
           highlightSpans: true,
-          sourceUrl: 'https://raw.githubusercontent.com/nipreps/nipreps.github.io/mkdocs/docs/assets/ORN-Workshop/presentation.md',
+          sourceUrl: 'presentation.md',
           ratio: '16:9'
       });
     </script>

docs/assets/bhd2020/index.html

@@ -259,7 +259,7 @@
           highlightLines: true,
           countIncrementalSlides: false,
           highlightSpans: true,
-          sourceUrl: 'https://raw.githubusercontent.com/nipreps/nipreps.github.io/mkdocs/docs/assets/bhd2020/presentation.md',
+          sourceUrl: 'presentation.md',
           ratio: '16:9'
       });
     </script>