reference: that looks like exclamations marks for some fonts

The sentences are also so short that they don't need periods at the end

Author: tshepang

src/doc/reference.md

@@ -3335,8 +3335,8 @@ is often called ‘unit’ or ‘the unit type’.
 
 Rust has two different types for a list of items:
 
-* `[T; N]`, an 'array'.
-* `&[T]`, a 'slice'.
+* `[T; N]`, an 'array'
+* `&[T]`, a 'slice'
 
 An array has a fixed size, and can be allocated on either the stack or the
 heap.