gh-139742: Add support for Python 3.14 t-string prefixes in IDLE colorizer and tests

Lib/idlelib/colorizer.py

@@ -47,7 +47,7 @@ def make_pat():
                    name not in keyword.kwlist]
     builtin = r"([^.'\"\\#]\b|^)" + any("BUILTIN", builtinlist) + r"\b"
     comment = any("COMMENT", [r"#[^\n]*"])
-    stringprefix = r"(?i:r|u|f|fr|rf|b|br|rb)?"
+    stringprefix = r"(?i:r|u|f|t|fr|rf|b|br|rb|rt|tr)?"
     sqstring = stringprefix + r"'[^'\\\n]*(\\.[^'\\\n]*)*'?"
     dqstring = stringprefix + r'"[^"\\\n]*(\\.[^"\\\n]*)*"?'
     sq3string = stringprefix + r"'''[^'\\]*((\\.|'(?!''))[^'\\]*)*(''')?"

Lib/idlelib/idle_test/test_colorizer.py

@@ -36,6 +36,7 @@ async def f(): await g()
     # All valid prefixes for unicode and byte strings should be colored.
     r'x', u'x', R'x', U'x', f'x', F'x'
     fr'x', Fr'x', fR'x', FR'x', rf'x', rF'x', Rf'x', RF'x'
+    tr'x', Tr'x', tR'x', TR'x', rt'x', rT'x', Rt'x', RT'x'
     b'x',B'x', br'x',Br'x',bR'x',BR'x', rb'x', rB'x',Rb'x',RB'x'
     # Invalid combinations of legal characters should be half colored.
     ur'x', ru'x', uf'x', fu'x', UR'x', ufr'x', rfu'x', xf'x', fx'x'

Misc/NEWS.d/next/IDLE/2025-10-08-08-35-50.gh-issue-139742.B3fZLg.rst

@@ -0,0 +1 @@
+Colorize t-string prefixes for template strings in IDLE, as done for f-string prefixes.