fix: run prettier only on js and json (#743)

Author: mwcz

.prettierignore

@@ -1,6 +1,13 @@
+# Ignore these files and file-types, regardless of where they are in the
+# directory tree.
+
 test
 package.json
 package-lock.json
+*.scss
+*.css
+*.html
+*.md
 
 generators/element/templates/*