tomllib: error when reading dicts with carriage returns or trailing commas

[lorcap]

Bug report

Bug description:

The following snippet throws a tomllib.TOMLDecodeError: Invalid initial character for a key part (at line 1, column 6):

import tomllib

tomllib.loads("""\
A = {
  a = 1,
}
""")

The following throws a tomllib.TOMLDecodeError: Invalid initial character for a key part (at line 1, column 14):

import tomllib

tomllib.loads("""\
A = { a = 1, }
""")

The same snippets run fine with tomli-2.4.1 installed via pip in the same virtual environment.

CPython versions tested on:

3.14

Operating systems tested on:

Linux

[StanFromIreland]

Newlines and trailing commas in inline tables are TOML 1.1.0 features (invalid in TOML 1.0.0 which 3.14's tomllib implements). Support was added in #142956 for 3.15 and newer. Try on 3.16, for example:

Python 3.16.0a0 (heads/main:8ca85b5bc5a, Jul 17 2026, 17:23:49) [Clang 21.1.8 (Fedora 21.1.8-4.fc43)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tomllib
... 
... tomllib.loads("""\
... A = {
...   a = 1,
... }
... """)
... 
{'A': {'a': 1}}