message: chore: add comments for unknowns in findPrivateMutations
diff: * | 4 | mutation in node, but not in sequence, aka "reversal" | yes | node.qry | node.ref |
  * | | (mutation in sequence that reverts the character to ref seq) | | | |
  * |---|--------------------------------------------------------------|---------|---------------|--------------|
  +* | 5 | unknown in sequence, mutation in node | no | N/A | N/A |
  +* |---|--------------------------------------------------------------|---------|---------------|--------------|
  +* | 6 | unknown in sequence, no mutation in node | no | N/A | N/A |
  +* |---|--------------------------------------------------------------|---------|---------------|--------------|
  *
  * At this point sequence have not yet become a new node on the tree, but is described by the results of the previous
  * analysis steps.
  @@ -95,7 +99,9 @@ namespace Nextclade {
  seqPositionsCovered.insert(pos);
  if (isUnknown(seqMut.qry)) {
  - // Skip nucleotide N and aminoacid X in sequence. We don't know whether they match the node character or not,
  + // Cases 5/6: Unknown in sequence
  + // Action: Skip nucleotide N and aminoacid X in sequence.
  + // We don't know whether they match the node character or not,
  // so we decide to not take them into account.
  continue;
  }
  