Update type hinting

Author: UsamaEquinorAFK

backend/src/acidwatch_api/models/phpitz.py

@@ -74,7 +74,7 @@ async def run(self) -> RunResult:
         return (concentrations_dict, TextResult(data=result))
 
     @staticmethod
-    def parse_phpitz_simple(text: str) -> dict:
+    def parse_phpitz_simple(text: str) -> dict[str, dict[str, float]]:
         result = {}
 
         lines = text.split("\n")
@@ -102,5 +102,4 @@ def parse_phpitz_simple(text: str) -> dict:
                         ),
                         "fugacity_coef": float(parts[4]),
                     }
-
         return result