fix(transformer): extract escaped chars out of the f-strings

Author: jdreo

src/ontoweaver/transformer.py

@@ -97,7 +97,8 @@ def __init__(self, raise_errors: bool = True):
         def __call__(self, columns, row, i):
             for key in columns:
                 if key not in row:
-                    self.error(f"Column '{key}' not found in data. Available columns:\n\t`{'`\n\t`'.join(row.keys())}`\n", section="map.call",
+                    available = "`\n\t`".join(row.keys())
+                    self.error(f"Column '{key}' not found in data. Available columns:\n\t`{available}`\n", section="map.call",
                                exception=exceptions.TransformerDataError)
                 else:
                     yield row[key]