message: fix: output aa context as string, not as array
diff: @@ -4,7 +4,7 @@ use crate::gene::gene::Gene;
  use crate::gene::gene_map::GeneMap;
  use crate::io::aa::Aa;
  use crate::io::letter::Letter;
  -use crate::io::nuc::Nuc;
  +use crate::io::nuc::{from_nuc_seq, Nuc};
  use crate::make_internal_report;
  use crate::translate::translate_genes::{Translation, TranslationMap};
  use crate::utils::error::keep_ok;
  @@ -23,8 +23,8 @@ pub struct AaSub {
  pub pos: usize,
  pub qry: Aa,
  pub codonNucRange: Range,
  - pub refContext: Vec<Nuc>,
  - pub queryContext: Vec<Nuc>,
  + pub refContext: String,
  + pub queryContext: String,
  pub contextNucRange: Range,
  }
  @@ -35,8 +35,8 @@ pub struct AaDel {
  pub reff: Aa,
  pub pos: usize,
  pub codonNucRange: Range,
  - pub refContext: Vec<Nuc>,
  - pub queryContext: Vec<Nuc>,
  + pub refContext: String,
  + pub queryContext: String,
  pub contextNucRange: Range,
  }
  @@ -147,8 +147,8 @@ fn find_aa_changes_for_gene(
  // Provide surrounding context in nucleotide sequences: 1 codon to the left and 1 codon to the right
  let context_begin = clamp(codon_begin - 3, 0, num_nucs);
  let context_end = clamp(codon_end + 3, 0, num_nucs);
  - let refContext = ref_seq[context_begin..context_end].to_vec();
  - let queryContext = qry_seq[context_begin..context_end].to_vec();
  + let refContext = from_nuc_seq(&ref_seq[context_begin..context_end]);
  + let queryContext = from_nuc_seq(&qry_seq[context_begin..context_end]);
  let codonNucRange = Range {
  begin: codon_begin,
  