correction README.md (#3794)

that that - that

---------

Signed-off-by: strmfos <[email protected]>
Co-authored-by: Andreas Fackler <[email protected]>

Author: strmfos

Diff for: examples/how-to/perform-http-requests/README.md

@@ -30,7 +30,7 @@ service perform the HTTP request and return only the deterministic parts of the
 
 ## HTTP requests using the service as an oracle
 
-The contract may call the service as an oracle. That means that that contracts sends a query to the
+The contract may call the service as an oracle. That means that contract sends a query to the
 service and waits for its response. The execution of the contract is metered by executed
 instruction, while the service executing as an oracle is metered by a coarse-grained timer. That
 allows the service to execute non-deterministically, and as long as it always returns a