doc: follow idiom in code snippet

diff --git a/src/doc/reference.md b/src/doc/reference.md
index 717c99901d1bc48c4f4b2a9409d6be62eaf8094e..efb986e19edfbbd0074d430d6b102b43c897a6a1 100644 (file)
--- a/src/doc/reference.md
+++ b/src/doc/reference.md
@@ -2762,7 +2762,7 @@ The following expressions are equivalent.
 let x = std::ops::Range {start: 0, end: 10};
 let y = 0..10;
 
-assert_eq!(x,y);
+assert_eq!(x, y);
 ```
 
 ### Unary operator expressions