Normalize capitalization in standard library tutorial sections

Co-authored-by: Copilot <copilot@github.com>

Author: ByteFlowing1337

Doc/tutorial/stdlib2.rst

@@ -1,7 +1,7 @@
 .. _tut-brieftourtwo:
 
 **********************************************
-Brief Tour of the Standard Library --- Part II
+Brief tour of the standard library --- part II
 **********************************************
 
 This second tour covers more advanced modules that support professional
@@ -10,7 +10,7 @@ programming needs.  These modules rarely occur in small scripts.
 
 .. _tut-output-formatting:
 
-Output Formatting
+Output formatting
 =================
 
 The :mod:`reprlib` module provides a version of :func:`repr` customized for
@@ -130,7 +130,7 @@ templates for XML files, plain text reports, and HTML web reports.
 
 .. _tut-binary-formats:
 
-Working with Binary Data Record Layouts
+Working with binary data record layouts
 =======================================
 
 The :mod:`struct` module provides :func:`~struct.pack` and
@@ -244,7 +244,7 @@ application.
 
 .. _tut-weak-references:
 
-Weak References
+Weak references
 ===============
 
 Python does automatic memory management (reference counting for most objects and
@@ -285,7 +285,7 @@ applications include caching objects that are expensive to create::
 
 .. _tut-list-tools:
 
-Tools for Working with Lists
+Tools for working with lists
 ============================
 
 Many data structure needs can be met with the built-in list type. However,
@@ -351,7 +351,7 @@ not want to run a full list sort::
 
 .. _tut-decimal-fp:
 
-Decimal Floating-Point Arithmetic
+Decimal floating-point arithmetic
 =================================
 
 The :mod:`decimal` module offers a :class:`~decimal.Decimal` datatype for