Fix typos in 3.10 "What's new" (GH-25104)

Author: donkirkby

Doc/whatsnew/3.10.rst

@@ -420,7 +420,7 @@ Several other key features:
 - Mapping patterns: ``{"bandwidth": b, "latency": l}`` captures the
   ``"bandwidth"`` and ``"latency"`` values from a dict.  Unlike sequence
   patterns, extra keys are ignored.  A wildcard ``**rest`` is also
-  supported.  (But ``**_`` would be redundant, so it not allowed.)
+  supported.  (But ``**_`` would be redundant, so is not allowed.)
 
 - Subpatterns may be captured using the ``as`` keyword::
 
@@ -462,13 +462,13 @@ Optional ``EncodingWarning`` and ``encoding="locale"`` option
 The default encoding of :class:`TextIOWrapper` and :func:`open` is
 platform and locale dependent. Since UTF-8 is used on most Unix
 platforms, omitting ``encoding`` option when opening UTF-8 files
-(e.g. JSON, YAML, TOML, Markdown) is very common bug. For example::
+(e.g. JSON, YAML, TOML, Markdown) is a very common bug. For example::
 
    # BUG: "rb" mode or encoding="utf-8" should be used.
    with open("data.json") as f:
-       data = json.laod(f)
+       data = json.load(f)
 
-To find this type of bugs, optional ``EncodingWarning`` is added.
+To find this type of bug, optional ``EncodingWarning`` is added.
 It is emitted when :data:`sys.flags.warn_default_encoding <sys.flags>`
 is true and locale-specific default encoding is used.