Fix reST markup in dataclasses.rst (GH-27843) (GH-27845)

The signature of field() had an extraneous colon at the end, causing it
to appear all bold and without the module name.
(cherry picked from commit d26dbba9297adb59bc49a6583c647804ef56fc58)

Co-authored-by: Jean-Abou-Samra <37271310+Jean-Abou-Samra@users.noreply.github.com>

Co-authored-by: Jean-Abou-Samra <37271310+Jean-Abou-Samra@users.noreply.github.com>
diff --git a/Doc/library/dataclasses.rst b/Doc/library/dataclasses.rst
index e203a1a..5da0553 100644
--- a/Doc/library/dataclasses.rst
+++ b/Doc/library/dataclasses.rst
@@ -205,7 +205,7 @@
    follows a field with a default value.  This is true whether this
    occurs in a single class, or as a result of class inheritance.
 
-.. function:: field(*, default=MISSING, default_factory=MISSING, init=True, repr=True, hash=None, compare=True, metadata=None, kw_only=MISSING):
+.. function:: field(*, default=MISSING, default_factory=MISSING, init=True, repr=True, hash=None, compare=True, metadata=None, kw_only=MISSING)
 
    For common and simple use cases, no other functionality is
    required.  There are, however, some dataclass features that