Fix off-by-one error in error column numbers

It turns out that marker column values from Saphyr are not actually 1-indexed.

src/metadata/error.rs

@@ -96,7 +96,7 @@ impl std::fmt::Display for ParseMetadataError {
             f,
             "encountered a YAML parsing error at line {} column {}: {}",
             self.marker.line(),
-            self.marker.col(),
+            self.marker.col() + 1,
             self.reason
         )
     }
@@ -357,7 +357,7 @@ impl std::fmt::Display for YamlMergeKeyError {
             f,
             "invalid YAML merge key value at line {} column {}: {}",
             self.start.line(),
-            self.start.col(),
+            self.start.col() + 1,
             self.yaml
         )
     }

src/metadata/yaml/merge.rs

@@ -90,7 +90,7 @@ mod tests {
             let error_message = process_merge_keys(yaml).unwrap_err().to_string();
 
             assert_eq!(
-                "invalid YAML merge key value at line 3 column 6: test",
+                "invalid YAML merge key value at line 3 column 7: test",
                 error_message
             );
         }
@@ -108,7 +108,7 @@ mod tests {
             let error_message = process_merge_keys(yaml).unwrap_err().to_string();
 
             assert_eq!(
-                "invalid YAML merge key value at line 4 column 17: test",
+                "invalid YAML merge key value at line 4 column 18: test",
                 error_message
             );
         }