posts/phrases: add learning is important

site-src/phrases.mdx

@@ -48,3 +48,11 @@ And I still mean it.
 
 If you were wondering, I write it in the Discord app on my phone before I go to sleep and send the message when I wake up;
 it only takes a few taps to write thanks to Gboard.
+
+## Learning is important
+Original. True, but sounds silly.
+You can say it when you learn or figure something out, especially when it's something small.
+
+Variations:
+- “Learning is so important.”
+- “It's so important to learn what a book is.”