Merge pull request #144 from kdnakt/translate-from_into

Translate untranslated line in from_into.md

Author: dalance

src/conversion/from_into.md

@@ -88,6 +88,7 @@ impl From<i32> for Number {
 fn main() {
     let int = 5;
     // Try removing the type annotation
+    // ここの型アノテーションを消してみましょう。
     let num: Number = int.into();
     println!("My number is {:?}", num);
 }