chore: stop editors from trimming fixtures (#191)

The probability that I remember to ctrl + k ctrl + s is roughly 0, so
this saves me a lot of pain.

.editorconfig

@@ -9,3 +9,7 @@ insert_final_newline = true
 
 [*.md]
 trim_trailing_whitespace = false
+
+# White space is important in code examples so we don't want to trim it
+[lib/__fixtures__/curriculum-helpers-javascript.ts]
+trim_trailing_whitespace = false