fix: numpy returns handles more name, type cases

src/griffe/docstrings/numpy.py

@@ -217,7 +217,9 @@ def _read_block(docstring: Docstring, *, offset: int) -> tuple[str, int]:
         |  # or
         (?P<name>{_RE_NAME})\s*:\s*  # just name
         |  # or
-        (?P<type>{_RE_TYPE})\s*  # just type
+        \s*:$  # no name, no type
+        |
+        :?\s*(?P<type>{_RE_TYPE})\s*  # just type
     )
     """,
     re.IGNORECASE | re.VERBOSE,

tests/test_docstrings/test_numpy.py

@@ -354,6 +354,12 @@ def test_returns_section(parse_numpy: ParserType) -> None:
         flag : bool
             Some kind
             of flag.
+        x :
+            Name only
+        :
+            No name or annotation
+        : int
+            Only annotation
     """
 
     sections, _ = parse_numpy(docstring)
@@ -367,6 +373,21 @@ def test_returns_section(parse_numpy: ParserType) -> None:
         DocstringReturn(name="", annotation="bool", description="Some kind\nof flag."),
     )
 
+    assert_element_equal(
+        sections[0].value[2],
+        DocstringReturn(name="", annotation=None, description="Name only"),
+    )
+
+    assert_element_equal(
+        sections[0].value[3],
+        DocstringReturn(name="", annotation=None, description="No name or annotation"),
+    )
+
+    assert_element_equal(
+        sections[0].value[4],
+        DocstringReturn(name="", annotation="int", description="Only annotation"),
+    )
+
 
 def test_yields_section(parse_numpy: ParserType) -> None:
     """Parse yields section.