Tweak column alignment in collections docs.

Doc/library/collections.rst

@@ -174,7 +174,7 @@ For example::
         >>> c = Counter()                           # a new, empty counter
         >>> c = Counter('gallahad')                 # a new counter from an iterable
         >>> c = Counter({'red': 4, 'blue': 2})      # a new counter from a mapping
-       >>> c = Counter(spam=8, eggs=1)              # a new counter from keyword args
+        >>> c = Counter(cats=4, dogs=8)             # a new counter from keyword args
 
    Counter objects have a dictionary interface except that they return a zero
    count for missing items instead of raising a :exc:`KeyError`::
@@ -207,10 +207,10 @@ For example::
 
    .. method:: most_common([n])
 
-      Return a list of the *n* most common elements and their counts from
-      the most common to the least.  If *n* is not specified or is ``None``,
-      return a list of all element counts in decreasing order of frequency.
-      Elements with equal counts are ordered arbitrarily::
+      Return a list of the *n* most common elements and their counts from the
+      most common to the least.  If *n* not specified, :func:`most_common`
+      returns *all* elements in the counter.  Elements with equal counts are
+      ordered arbitrarily::
 
             >>> Counter('abracadabra').most_common(3)
             [('a', 5), ('r', 2), ('b', 2)]
@@ -225,16 +225,9 @@ For example::
    .. method:: update([iterable-or-mapping])
 
       Elements are counted from an *iterable* or added-in from another
-       *mapping* (or counter).  Like :meth:`dict.update` but adds-in counts
+      *mapping* (or counter).  Like :meth:`dict.update` but adds counts
       instead of replacing them.  Also, the *iterable* is expected to be a
-       sequence of elements, not a sequence of ``(key, value)`` pairs::
-
-            >>> c = Counter('which')
-            >>> c.update('witch')           # add elements from another iterable
-            >>> d = Counter('watch')
-            >>> c.update(d)                 # add elements from another counter
-            >>> c['h']                      # four 'h' in which, witch, and watch
-            4
+      sequence of elements, not a sequence of ``(key, value)`` pairs.
 
 Common patterns for working with :class:`Counter` objects::