[cleanup]  cleanup redirect methods

- add a new redirects method to BaseSite that returns the generic
  redirect tag list (previously returned by BaseSite.redirect()
- add a new redirects method to APISite that returns the
  redirect tag list extracted from getmagicwords('redirect')
- return the default redirect tag with BaseSite.redirect() instead of
  a list. This enables to get the default tag also from APISite if
  APISite.redirects is defined
- move redirect_regex method from APISite to BaseSite but simplify
  the implementation. It is not necessary to assume that
  getmagicwords('redirect') does not exists; it was a guess of of the
  very first 2.0 implemetation and was implemented as the redirect tags
  were part of the family files sometime in 2008.
- remove deprecated redirectRegex

Bug: T347226
Change-Id: I3647cf8cb154686f075bc53a054b937675d74765
---
M ROADMAP.rst
M pywikibot/site/_apisite.py
M pywikibot/site/_basesite.py
3 files changed, 65 insertions(+), 46 deletions(-)

diff --git a/ROADMAP.rst b/ROADMAP.rst
index 9814645..d91c5b4 100644
--- a/ROADMAP.rst
+++ b/ROADMAP.rst
@@ -76,4 +76,3 @@
 * 6.2.0: Throttle.multiplydelay attribute is deprecated
 * 6.2.0: SequenceOutputter.format_list() is deprecated in favour of 'out' property
 * 6.0.0: config.register_family_file() is deprecated
-* 5.5.0: APISite.redirectRegex() will be removed in favour of APISite.redirect_regex()
diff --git a/pywikibot/site/_apisite.py b/pywikibot/site/_apisite.py
index 33d1752..ba3e8ca 100644
--- a/pywikibot/site/_apisite.py
+++ b/pywikibot/site/_apisite.py
@@ -17,7 +17,7 @@
 from pywikibot import login
 from pywikibot.backports import DefaultDict, Dict, List, Match
 from pywikibot.backports import OrderedDict as OrderedDictType
-from pywikibot.backports import Iterable, Pattern, Set, Tuple, removesuffix
+from pywikibot.backports import Iterable, Set, Tuple, removesuffix
 from pywikibot.comms import http
 from pywikibot.data import api
 from pywikibot.exceptions import (
@@ -1036,32 +1036,18 @@
             return self._magicwords[word]
         return [word]
 
-    def redirect(self) -> str:
-        """Return the localized #REDIRECT keyword."""
-        # return the magic word without the preceding '#' character
-        return self.getmagicwords('redirect')[0].lstrip('#')
+    def redirects(self) -> List[str]:
+        """Return a list of localized tags for the site without preceding '#'.
 
-    @deprecated('redirect_regex', since='5.5.0')
-    def redirectRegex(self) -> Pattern[str]:  # noqa: N802
-        """Return a compiled regular expression matching on redirect pages."""
-        return self.redirect_regex
+        .. seealso::
+           :meth:`BaseSite.redirect()
+           <pywikibot.site._basesite.BaseSite.redirect>` and
+           :meth:`BaseSite.redirects()
+           <pywikibot.site._basesite.BaseSite.redirects>`
 
-    @property
-    def redirect_regex(self) -> Pattern[str]:
-        """Return a compiled regular expression matching on redirect pages.
-
-        Group 1 in the regex match object will be the target title.
-
+        .. versionadded:: 8.4
         """
-        # NOTE: this is needed, since the API can give false positives!
-        try:
-            keywords = {s.lstrip('#') for s in self.getmagicwords('redirect')}
-            keywords.add('REDIRECT')  # just in case
-            pattern = '(?:' + '|'.join(keywords) + ')'
-        except KeyError:
-            # no localized keyword for redirects
-            pattern = None
-        return super().redirectRegex(pattern)
+        return [s.lstrip('#') for s in self.getmagicwords('redirect')]
 
     def pagenamecodes(self) -> List[str]:
         """Return list of localized PAGENAME tags for the site."""
diff --git a/pywikibot/site/_basesite.py b/pywikibot/site/_basesite.py
index 7292efc..ea47b94 100644
--- a/pywikibot/site/_basesite.py
+++ b/pywikibot/site/_basesite.py
@@ -11,7 +11,7 @@
 from warnings import warn
 
 import pywikibot
-from pywikibot.backports import Pattern
+from pywikibot.backports import List, Pattern
 from pywikibot.exceptions import (
     Error,
     FamilyMaintenanceWarning,
@@ -242,26 +242,36 @@
         """Return dict of valid namespaces on this wiki."""
         return NamespacesDict(self._build_namespaces())
 
-    def ns_normalize(self, value):
-        """
-        Return canonical local form of namespace name.
+    def ns_normalize(self, value: str):
+        """Return canonical local form of namespace name.
 
         :param value: A namespace name
-        :type value: str
-
         """
         index = self.namespaces.lookup_name(value)
         return self.namespace(index)
 
-    def redirect(self):
-        """Return list of localized redirect tags for the site."""
+    def redirect(self) -> str:
+        """Return a default redirect tag for the site.
+
+        .. versionchanged:: 8.4
+           return a single generic redirect tag instead of a list of
+           tags. For the list use :meth:`redirects` instead.
+        """
+        return self.redirects()[0]
+
+    def redirects(self) -> List[str]:
+        """Return list of generic redirect tags for the site.
+
+        .. seealso:: :meth:`redirect` for the default redirect tag.
+        .. versionadded:: 8.4
+        """
         return ['REDIRECT']
 
-    def pagenamecodes(self):
+    def pagenamecodes(self) -> List[str]:
         """Return list of localized PAGENAME tags for the site."""
         return ['PAGENAME']
 
-    def pagename2codes(self):
+    def pagename2codes(self) -> List[str]:
         """Return list of localized PAGENAMEE tags for the site."""
         return ['PAGENAMEE']
 
@@ -337,22 +347,22 @@
         linkfam, linkcode = pywikibot.Link(text, self).parse_site()
         return linkfam != self.family.name or linkcode != self.code
 
-    def redirectRegex(  # noqa: N802
-        self,
-        pattern: Optional[str] = None
-    ) -> Pattern[str]:
+    @property
+    def redirect_regex(self) -> Pattern[str]:
         """Return a compiled regular expression matching on redirect pages.
 
         Group 1 in the regex match object will be the target title.
 
+        A redirect starts with hash (#), followed by a keyword, then
+        arbitrary stuff, then a wikilink. The wikilink may contain a
+        label, although this is not useful.
+
+        .. versionadded:: 8.4
+           moved from class:`APISite<pywikibot.site._apisite.APISite>`
         """
-        if pattern is None:
-            pattern = 'REDIRECT'
-        # A redirect starts with hash (#), followed by a keyword, then
-        # arbitrary stuff, then a wikilink. The wikilink may contain
-        # a label, although this is not useful.
-        return re.compile(r'\s*#{pattern}\s*:?\s*\[\[(.+?)(?:\|.*?)?\]\]'
-                          .format(pattern=pattern), re.IGNORECASE | re.DOTALL)
+        tags = '|'.join(self.redirects())
+        return re.compile(fr'\s*#(?:{tags})\s*:?\s*\[\[(.+?)(?:\|.*?)?\]\]',
+                          re.IGNORECASE | re.DOTALL)
 
     def sametitle(self, title1: str, title2: str) -> bool:
         """

