gh-133361: move the explanation of dict equal before its use (#133424)

Also move up the explanation of insertion order preservation.  Both paragraphs seemed out of place down where they were.
---------

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index 39aaa5da0786f8283b54f4351a78fbddcb1cac47..61d39a6671caed5c2ab949df16993f36d9476e6b 100644 (file)
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -4823,7 +4823,13 @@ can be used interchangeably to index the same dictionary entry.
    being added is already present, the value from the keyword argument
    replaces the value from the positional argument.
 
-   To illustrate, the following examples all return a dictionary equal to
+   Providing keyword arguments as in the first example only works for keys that
+   are valid Python identifiers.  Otherwise, any valid keys can be used.
+
+   Dictionaries compare equal if and only if they have the same ``(key,
+   value)`` pairs (regardless of ordering). Order comparisons ('<', '<=', '>=', '>') raise
+   :exc:`TypeError`.  To illustrate dictionary creation and equality,
+   the following examples all return a dictionary equal to
    ``{"one": 1, "two": 2, "three": 3}``::
 
       >>> a = dict(one=1, two=2, three=3)
@@ -4838,6 +4844,27 @@ can be used interchangeably to index the same dictionary entry.
    Providing keyword arguments as in the first example only works for keys that
    are valid Python identifiers.  Otherwise, any valid keys can be used.
 
+   Dictionaries preserve insertion order.  Note that updating a key does not
+   affect the order.  Keys added after deletion are inserted at the end. ::
+
+      >>> d = {"one": 1, "two": 2, "three": 3, "four": 4}
+      >>> d
+      {'one': 1, 'two': 2, 'three': 3, 'four': 4}
+      >>> list(d)
+      ['one', 'two', 'three', 'four']
+      >>> list(d.values())
+      [1, 2, 3, 4]
+      >>> d["one"] = 42
+      >>> d
+      {'one': 42, 'two': 2, 'three': 3, 'four': 4}
+      >>> del d["two"]
+      >>> d["two"] = None
+      >>> d
+      {'one': 42, 'three': 3, 'four': 4, 'two': None}
+
+   .. versionchanged:: 3.7
+      Dictionary order is guaranteed to be insertion order.  This behavior was
+      an implementation detail of CPython from 3.6.
 
    These are the operations that dictionaries support (and therefore, custom
    mapping types should support too):
@@ -5008,32 +5035,6 @@ can be used interchangeably to index the same dictionary entry.
 
       .. versionadded:: 3.9
 
-   Dictionaries compare equal if and only if they have the same ``(key,
-   value)`` pairs (regardless of ordering). Order comparisons ('<', '<=', '>=', '>') raise
-   :exc:`TypeError`.
-
-   Dictionaries preserve insertion order.  Note that updating a key does not
-   affect the order.  Keys added after deletion are inserted at the end. ::
-
-      >>> d = {"one": 1, "two": 2, "three": 3, "four": 4}
-      >>> d
-      {'one': 1, 'two': 2, 'three': 3, 'four': 4}
-      >>> list(d)
-      ['one', 'two', 'three', 'four']
-      >>> list(d.values())
-      [1, 2, 3, 4]
-      >>> d["one"] = 42
-      >>> d
-      {'one': 42, 'two': 2, 'three': 3, 'four': 4}
-      >>> del d["two"]
-      >>> d["two"] = None
-      >>> d
-      {'one': 42, 'three': 3, 'four': 4, 'two': None}
-
-   .. versionchanged:: 3.7
-      Dictionary order is guaranteed to be insertion order.  This behavior was
-      an implementation detail of CPython from 3.6.
-
    Dictionaries and dictionary views are reversible. ::
 
       >>> d = {"one": 1, "two": 2, "three": 3, "four": 4}