[3.9] bpo-40833: Clarify Path.rename doc-string regarding relative paths (GH-20554)

(cherry picked from commit f97e42ef4d)

Co-authored-by: Ram Rachum <ram@rachum.com>

Doc/library/pathlib.rst

@@ -1008,6 +1008,10 @@ call fails (for example because the path doesn't exist).
       >>> target.open().read()
       'some text'
 
+   The target path may be absolute or relative. Relative paths are interpreted
+   relative to the current working directory, *not* the directory of the Path
+   object.
+
    .. versionchanged:: 3.8
       Added return value, return the new Path instance.
 
@@ -1018,6 +1022,10 @@ call fails (for example because the path doesn't exist).
    instance pointing to *target*.  If *target* points to an existing file or
    directory, it will be unconditionally replaced.
 
+   The target path may be absolute or relative. Relative paths are interpreted
+   relative to the current working directory, *not* the directory of the Path
+   object.
+
    .. versionchanged:: 3.8
       Added return value, return the new Path instance.
 

Lib/pathlib.py

@@ -1366,17 +1366,26 @@ class Path(PurePath):
 
     def rename(self, target):
         """
-        Rename this path to the given path,
-        and return a new Path instance pointing to the given path.
+        Rename this path to the target path.
+
+        The target path may be absolute or relative. Relative paths are
+        interpreted relative to the current working directory, *not* the
+        directory of the Path object.
+
+        Returns the new Path instance pointing to the target path.
         """
         self._accessor.rename(self, target)
         return self.__class__(target)
 
     def replace(self, target):
         """
-        Rename this path to the given path, clobbering the existing
-        destination if it exists, and return a new Path instance
-        pointing to the given path.
+        Rename this path to the target path, overwriting if that path exists.
+
+        The target path may be absolute or relative. Relative paths are
+        interpreted relative to the current working directory, *not* the
+        directory of the Path object.
+
+        Returns the new Path instance pointing to the target path.
         """
         self._accessor.replace(self, target)
         return self.__class__(target)