refactor: typings

Author: gnikit

fortls/intrinsics.py

@@ -29,13 +29,13 @@ def __init__(
         self,
         name: str,
         type: int,
-        doc_str: str = "",
+        doc_str: str | None = None,
         args: str = "",
         parent=None,
     ):
         self.name: str = name
         self.type: int = type
-        self.doc_str: str = doc_str
+        self.doc_str: str | None = doc_str
         self.args: str = args.replace(" ", "")
         self.parent = parent
         self.file_ast: FortranAST = intrinsic_ast