Fixes in diagnostics to str conversion

Author: insolor

df_translation_toolkit/validation/validation_models.py

@@ -30,7 +30,7 @@ def __init__(self, problems: list[ValidationProblem]) -> None:
         self.problems = problems
 
     def __str__(self) -> str:
-        return "\n".join(str(error) for error in self.problems)
+        return "\n".join(f" {error}" for error in self.problems)
 
 
 @dataclass
@@ -41,7 +41,7 @@ class ProblemInfo:
 
     def __str__(self) -> str:
         problems_text = "\n".join(str(problem) for problem in self.problems)
-        return f"Problematic tag pair: {self.original!r}, {self.translation!r}\nProblems:\n{problems_text}"
+        return f"Problematic pair: {self.original!r}, {self.translation!r}\nProblems:\n{problems_text}"
 
     def contains_problems(self) -> bool:
         return bool(self.problems)