STY: Tweak if statement (#3176)

Author: j-t-1

pypdf/generic/_base.py

@@ -569,7 +569,7 @@ def write_to_stream(
     @staticmethod
     def read_from_stream(stream: StreamType) -> Union["NumberObject", "FloatObject"]:
         num = read_until_regex(stream, NumberObject.NumberPattern)
-        if num.find(b".") != -1:
+        if b"." in num:
             return FloatObject(num)
         return NumberObject(num)