Drop the floatstr comment and trim the NEWS entry

Per review: the comment and the implementation detail in the NEWS entry are
not relevant to end users.

Author: gaborbernat

Lib/json/encoder.py

@@ -233,9 +233,6 @@ def iterencode(self, o, _one_shot=False):
                 self.key_separator, self.item_separator, self.sort_keys,
                 self.skipkeys, self.allow_nan)
         else:
-            # floatstr is only needed by the pure-Python encoder; defining it
-            # lazily avoids building this closure on every encode that takes
-            # the C fast path above.
             def floatstr(o, allow_nan=self.allow_nan,
                     _repr=float.__repr__, _inf=INFINITY, _neginf=-INFINITY):
                 # Check for specials.  Note that this type of test is processor

Misc/NEWS.d/next/Library/2026-06-02-15-45-00.gh-issue-150820.W7tpO7.rst

@@ -1,3 +1 @@
-Speed up :func:`json.dumps` for small documents by building the float
-formatting helper only on the slower Python encoding path instead of on every
-call. Patch by Bernát Gábor.
+Speed up :func:`json.dumps` for small documents. Patch by Bernát Gábor.