Fix syntax

Author: kabilar

docs/src/query/restrict.md

@@ -5,7 +5,7 @@
 The restriction operator `A & cond` selects the subset of entities from `A` that meet 
 the condition `cond`.
 The exclusion operator `A - cond` selects the complement of restriction, i.e. the 
-subset of entities from  `A` that do not meet the condition `cond`.
+subset of entities from `A` that do not meet the condition `cond`.
 
 Restriction and exclusion.