Add support for PEP701

* fstring don't emit tk.STRING in python3.12, reattach the now separate
  tokens and pass them to Docstring preserving previous behavior.

Closes: #646
Signed-off-by: Alfred Wingate <parona@protonmail.com>

docs/release_notes.rst

@@ -4,6 +4,14 @@ Release Notes
 **pydocstyle** version numbers follow the
 `Semantic Versioning <http://semver.org/>`_ specification.
 
+
+Current development version
+---------------------------
+
+Bug Fixes
+
+* Add support for PEP-701 fixing fstring parsing in python3.12 (#656).
+
 6.3.0 - January 17th, 2023
 --------------------------
 

src/pydocstyle/parser.py

@@ -479,6 +479,20 @@ def parse_docstring(self):
             )
             self.stream.move()
             return docstring
+        if (sys.version_info.major, sys.version_info.minor) >= (
+            3,
+            12,
+        ) and self.current.kind == tk.FSTRING_START:
+            # Reattach fstring tokens together to deal with PEP 701 in python3.12
+            value = self.current.value
+            start = self.current.start[0]
+            while self.current.kind != tk.FSTRING_END:
+                self.stream.move()
+                value += self.current.value
+            end = self.current.end[0]
+            docstring = Docstring(value, start, end)
+            self.stream.move()
+            return docstring
         return None
 
     def parse_decorators(self):