refactor: write characters to screen one at a time. While this seems …

…like it would decrease performance, the python file.write method is buffered, so it shouldn't make a difference

src/acurses.py

@@ -147,9 +147,11 @@ def addstr(self, *args: Any, **kwargs: Any) -> None:
     @_addstr.register(str)
     def _(self, text: str, attr: int = 0) -> None:
         ansi_attrs = self._parse_attrs(attr)
-        stdout.write(
-            f"{ansi_attrs}{text[:self._width]}{_ANSI_RESET if ansi_attrs else ''}"
-        )
+        stdout.write(ansi_attrs)
+        for char in text[:self._width]:
+            stdout.write(char)
+        if ansi_attrs:
+            stdout.write(_ANSI_RESET)
         stdout.flush()
 
     @_addstr.register(int)