Merge pull request #669 from coder3112/grammar_error_doc

Fix grammar in dups-and-sups.md

docs/dups-and-sups.md

@@ -31,7 +31,7 @@ let {x1 x2} = {1 2}
 ```
 
 Due to how duplications are compiled, when two dups interact, they destructively interfere with each other.
-In this case the result doesn't follow the expected behavior (it's well defined at the HVM level, but doesn't is incorrect at a lambda-calculus level).
+In this case the result doesn't follow the expected behavior (it's well defined at the HVM level, but is incorrect at a lambda-calculus level).
 
 That imposes a strong restriction on correct Bend programs: a variable should not duplicate another variable that itself duplicates some variables.
 
@@ -57,4 +57,4 @@ def main:
 ```
 
 In this case, we can only have one source of duplication, or our results will be incorrect.
-Either List/map is linear (doesn't duplicate `f`) or the passed function is linear (doesn't duplicate `x` or any other variable inside it).
+Either List/map is linear (doesn't duplicate `f`) or the passed function is linear (doesn't duplicate `x` or any other variable inside it).