Panic on quoted text ending with period followed by spaced dots

[santhoshtr]

sentencex.segment() panics with a Rust begin <= end slice index error when the input
contains a straight double-quoted string whose last character before the closing quote is
a period, followed by a space and two or more consecutive dots.

The panic propagates to Python as pyo3_runtime.PanicException (not a Python Exception),
so it cannot be caught by except Exception — only except BaseException.

Minimal reproduction

from sentencex import segment
list(segment("ml", '"." .. a'))   # panics
list(segment("en", '"X." .. a'))  # panics

Both lines raise:

pyo3_runtime.PanicException: begin <= end (7 <= 6) when slicing `"." .. a`[...]

Rust stderr:

thread '<unnamed>' panicked at src/languages/language.rs:265:47:
begin <= end (7 <= 6) when slicing `"." .. a`[...]