(NFC) Remove unused truncated variable.

It is not used and hasn't been, so we can remove it.

Author: AZero13

Python/_warnings.c

@@ -683,7 +683,6 @@ show_warning(PyThreadState *tstate, PyObject *filename, int lineno,
         const void *data;
         Py_ssize_t i, len;
         Py_UCS4 ch;
-        PyObject *truncated;
 
         kind = PyUnicode_KIND(sourceline);
         data = PyUnicode_DATA(sourceline);
@@ -694,12 +693,7 @@ show_warning(PyThreadState *tstate, PyObject *filename, int lineno,
                 break;
         }
 
-        truncated = PyUnicode_Substring(sourceline, i, len);
-        if (truncated == NULL)
-            goto error;
-
         PyFile_WriteObject(sourceline, f_stderr, Py_PRINT_RAW);
-        Py_DECREF(truncated);
         PyFile_WriteString("\n", f_stderr);
     }
     else {