add escape char attribute

PyTeX/format/formatting_config.py

@@ -30,6 +30,8 @@ class FormattingConfig(Config):
         self._include_ins: Optional[bool] = True
         self._use_docstrip_guards: Optional[List[str]] = None
 
+        self._escape_character: Optional[str] = None
+
     def merge_with(self, other, strict: bool = False):
         """
         Merges the other config into this one
@@ -182,6 +184,13 @@ class FormattingConfig(Config):
         else:
             return self._use_docstrip_guards
 
+    @property
+    def escape_character(self) -> str:
+        if self._escape_character is None:
+            return '!'
+        else:
+            return self._escape_character
+
 
 class DocFormattingConfig:
     def __init__(self):