Proof Set and Chain Test Vectors: punctuation fix.

Co-authored-by: Ted Thibodeau Jr <[email protected]>

index.html

@@ -2051,7 +2051,7 @@ <h4>Proof Set</h4>
 Per the algorithm of <a data-cite="vc-data-integrity#add-proof-set/chain">
 Section 4.4: Add Proof Set/Chain</a> in [[VC-DATA-INTEGRITY]],
 we create an array variable, <var>allProofs</var>, and add the proof from the
-starting document to it. Since there is no `previousProof` attribute no
+starting document to it. Since there is no `previousProof` attribute, no
 modification of `unsignedDocument` is needed prior to computing the signed proof
 in step 6 of <a data-cite="vc-data-integrity#add-proof-set/chain">
 Section 4.4: Add Proof Set/Chain</a> in