DOC: Fix title capitalization in documentation files

Author: Wong2333

doc/source/whatsnew/v0.25.0.rst

@@ -551,7 +551,7 @@ with :attr:`numpy.nan` in the case of an empty :class:`DataFrame` (:issue:`26397
 ``__str__`` methods now call ``__repr__`` rather than vice versa
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Pandas has until now mostly defined string representations in a pandas objects'
+pandas has until now mostly defined string representations in a pandas objects'
 ``__str__``/``__unicode__``/``__bytes__`` methods, and called ``__str__`` from the ``__repr__``
 method, if a specific ``__repr__`` method is not found. This is not needed for Python3.
 In pandas 0.25, the string representations of pandas objects are now generally

doc/source/whatsnew/v1.2.0.rst

@@ -64,7 +64,7 @@ By default, duplicates continue to be allowed.
     label
     a        [0, 1]
 
-Pandas will propagate the ``allows_duplicate_labels`` property through many operations.
+pandas will propagate the ``allows_duplicate_labels`` property through many operations.
 
 .. code-block:: ipython
 

doc/source/whatsnew/v3.0.0.rst

@@ -269,7 +269,7 @@ This change also applies to :meth:`.DataFrameGroupBy.value_counts`. Here, there
 Increased minimum version for Python
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Pandas 3.0.0 supports Python 3.10 and higher.
+pandas 3.0.0 supports Python 3.10 and higher.
 
 Increased minimum versions for dependencies
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -305,7 +305,7 @@ See :ref:`install.dependencies` and :ref:`install.optional_dependencies` for mor
 ``pytz`` now an optional dependency
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Pandas now uses :py:mod:`zoneinfo` from the standard library as the default timezone implementation when passing a timezone
+pandas now uses :py:mod:`zoneinfo` from the standard library as the default timezone implementation when passing a timezone
 string to various methods. (:issue:`34916`)
 
 *Old behavior:*