test: pin whole-word matching for Turkic marker regex; docs: clarify guard asymmetry

Addresses PR review feedback on #198:
- Add a regex-level test confirming is_turkic_patronymic_marker() only
  matches whole marker words, not substrings (e.g. "ogluu", "Bogluchik"),
  guarding against a future accidental .match()->.search() swap.
- Soften docs/customize.rst's "mirroring the strictness of the
  East-Slavic guard" claim, which overstated parity: the Turkic guard
  has no middle-token disambiguation check analogous to East-Slavic's,
  since marker words are a small closed set unlikely to coincide with
  an ordinary given name.

Author: derek73

docs/customize.rst

@@ -140,14 +140,17 @@ Natural order (``"Vusal Said oglu Aliyev"``) and comma order
 and are left unchanged.
 
 Detection is scoped strictly to the 4-token shape (single-token first/last,
-exactly two middle tokens, last token a recognised marker) — mirroring the
-strictness of the East-Slavic guard above. Recognised markers cover common
-transliterations and native orthographies: Latin ``oglu``, ``oğlu``,
-``ogly``, ``ogli``, ``o'g'li`` (and its Uzbek modifier-apostrophe and
-right-single-quote variants), ``qizi``, ``qızı``, ``kizi``, ``kyzy``,
-``gyzy``, ``uly``, ``uulu``; and Cyrillic ``оглу``, ``оглы``, ``оғлу``,
-``ўғли``, ``угли``, ``кызы``, ``гызы``, ``қызы``, ``қизи``, ``улы``,
-``ұлы``, ``уулу``. Matching is case-insensitive.
+exactly two middle tokens, last token a recognised marker) — matching the
+East-Slavic guard's token-count strictness above. Unlike that guard, there's
+no additional check on the given-name token, since Turkic markers are a
+small, closed set unlikely to coincide with an ordinary given name (whereas
+East-Slavic patronymic suffixes can coincide with real Western surnames).
+Recognised markers cover common transliterations and native orthographies:
+Latin ``oglu``, ``oğlu``, ``ogly``, ``ogli``, ``o'g'li`` (and its Uzbek
+modifier-apostrophe and right-single-quote variants), ``qizi``, ``qızı``,
+``kizi``, ``kyzy``, ``gyzy``, ``uly``, ``uulu``; and Cyrillic ``оглу``,
+``оглы``, ``оғлу``, ``ўғли``, ``угли``, ``кызы``, ``гызы``, ``қызы``,
+``қизи``, ``улы``, ``ұлы``, ``уулу``. Matching is case-insensitive.
 
 
 Suppressing Middle Names

tests/test_turkic_patronymic_order.py

@@ -3,6 +3,18 @@
 from tests.base import HumanNameTestBase
 
 
+def test_marker_is_whole_word_not_substring() -> None:
+    # is_turkic_patronymic_marker() deliberately uses whole-word .match(),
+    # not suffix .search() (unlike is_east_slavic_patronymic()) — pin this
+    # so a future .match()->.search() slip doesn't silently start matching
+    # surnames/given-names that merely contain a marker as a substring.
+    C = Constants()
+    assert not C.regexes.turkic_patronymic_marker.match("ogluu")
+    assert not C.regexes.turkic_patronymic_marker.match("Bogluchik")
+    assert not C.regexes.turkic_patronymic_marker_cyrillic.match("оглуш")
+    assert not C.regexes.turkic_patronymic_marker_cyrillic.match("Оглуев")
+
+
 class TurkicPatronymicNameOrderReorderTests(HumanNameTestBase):
     """Names that SHOULD be rotated when the flag is on."""