Update draft-irtf-cfrg-vdaf.md

Co-authored-by: Shan <[email protected]>

draft-irtf-cfrg-vdaf.md

@@ -2137,7 +2137,7 @@ as long as `joint_rand` and `query_rand` are generated uniform randomly, the
 output is `False` with high probability. False positives are possible: there is
 a small probability that a verifier accepts an invalid input as valid. An FLP
 is said to be "sound" if this probability is sufficiently small. The soundness
-of the FLP depends on a variety of parameters, like like the length of the
+of the FLP depends on a variety of parameters, like the length of the
 input and the size of the field. See {{flp-generic}} for details.
 
 We remark that {{BBCGGI19}} defines a much larger class of fully linear proof