doc/tutorial: removing duplicate word in bounds

Change-Id: Idd44ea8f336dd91e7602ead5bddb01357fe2004a
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/4041
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/doc/tutorial/basics/2_types/70_bounds.txt b/doc/tutorial/basics/2_types/70_bounds.txt
index 9f36809..5e8a073 100644
--- a/doc/tutorial/basics/2_types/70_bounds.txt
+++ b/doc/tutorial/basics/2_types/70_bounds.txt
@@ -7,7 +7,7 @@
 
 -- text.md --
 Bounds define a lower bound, upper bound, or inequality for a certain value.
-They work on numbers, strings, bytes, and and null.
+They work on numbers, strings, bytes and null.
 
 The bound is defined for all values for which the corresponding comparison
 operation is define.