const.py, rigo: remove remaining Python 2 dead code

Simplify const_isfileobj(), const_isnumber(), const_debug_write()
and remove unreachable code in rigo/rigo/utils.py::prepare_markup().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/entropy/const.py

@@ -1439,20 +1439,14 @@ def const_isfileobj(obj):
     """
     Return whether obj is a file object
     """
-    if const_is_python3():
-        import io
-        return isinstance(obj, io.IOBase)
-    else:
-        return isinstance(obj, file)
+    import io
+    return isinstance(obj, io.IOBase)
 
 def const_isnumber(obj):
     """
     Return whether obj is an int, long object.
     """
-    if const_is_python3():
-        return isinstance(obj, int)
-    else:
-        return isinstance(obj, (int, long,))
+    return isinstance(obj, int)
 
 def const_cmp(a, b):
     """
@@ -1575,12 +1569,9 @@ def const_debug_write(identifier, msg, force = False, stdout=None):
             teal(repr(current_thread.daemon)), darkgreen(repr(time.time())),
             darkred(identifier),)
         with _DEBUG_W_LOCK:
-            if const_is_python3():
-                stdout.buffer.write(
-                    const_convert_to_rawstring(th_identifier) + \
-                        b" " + const_convert_to_rawstring(msg) + b"\n")
-            else:
-                stdout.write("%s: %s" % (th_identifier, msg + "\n"))
+            stdout.buffer.write(
+                const_convert_to_rawstring(th_identifier) + \
+                    b" " + const_convert_to_rawstring(msg) + b"\n")
             stdout.flush()
 
 def const_get_caller():

rigo/rigo/utils.py

@@ -204,9 +204,4 @@ def prepare_markup(text):
     """
     Convert text to raw bytestring to make GTK3 happy.
     """
-    return text  # str()-strings just work
-    if const_isunicode(text):
-        return \
-            const_convert_to_rawstring(
-                text, from_enctype=etpConst['conf_encoding'])
     return text