Fix output format in triangle mode (#31)

* Fix --full-matrix output format in triangle mode for -o option

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Co-authored-by: Florian Plaza Onate <fplazaonate@gmt.bio>

src/file_io.rs

@@ -416,7 +416,7 @@ pub fn write_phyllip_matrix(
             write!(&mut af_file, "{}", name).unwrap();
             let end = sketches.len();
             for j in 0..end {
-                let full_cond = (full_matrix && i >= j) || (i > j);
+                let full_cond = full_matrix || (i > j);
                 if i == j {
                     if full_cond {
                         write!(&mut ani_file, "\t{:.2}", perfect).unwrap();