Update migrating-to-v1.html

minor fix

docs/documentation/start/migrating-to-v1.html

@@ -12,7 +12,7 @@
 ---
 
 {% capture markdown %}
-Bulma v1 is basically a **full rewrite** of the framework using [**Dart Sass**](https://sass-lang.com/dart-sass/), which is the the primary implementation of Sass. While this affects a few development details, everything has been done to make the transition **as easy as possible**.
+Bulma v1 is basically a **full rewrite** of the framework using [**Dart Sass**](https://sass-lang.com/dart-sass/), which is the primary implementation of Sass. While this affects a few development details, everything has been done to make the transition **as easy as possible**.
 {% endcapture %}
 
 {% include markdown.html content=markdown %}