Add type annotations

Author: youtux

src/pytest_bdd/exceptions.py

@@ -26,7 +26,7 @@ class NoScenariosFound(Exception):
 class GherkinParseError(Exception):
     """Base class for all Gherkin parsing errors."""
 
-    def __init__(self, message, line, line_content, filename):
+    def __init__(self, message: str, line: int, line_content: str, filename: str):
         super().__init__(message)
         self.message = message
         self.line = line
@@ -36,7 +36,7 @@ def __init__(self, message, line, line_content, filename):
         self.line_content = line_content
         self.filename = filename
 
-    def __str__(self):
+    def __str__(self) -> str:
         return f"{self.message}\nLine number: {self.line}\nLine: {self.line_content}\nFile: {self.filename}"