Finish the first pass of the language reference update.

Document extended iterable unpacking, raising and catching exceptions, class decorators, etc.
A few notable things are not documented yet, I've added XXX comments about that.

Doc/library/exceptions.rst

@@ -46,6 +46,7 @@ defining exceptions is available in the Python Tutorial under
 
 The following exceptions are only used as base classes for other exceptions.
 
+.. XXX document with_traceback()
 
 .. exception:: BaseException
 

Doc/reference/expressions.rst

@@ -183,6 +183,9 @@ by considering each of the :keyword:`for` or :keyword:`if` clauses a block,
 nesting from left to right, and evaluating the expression to produce an element
 each time the innermost block is reached.
 
+Note that the comprehension is executed in a separate scope, so names assigned
+to in the target list don't "leak" in the enclosing scope.
+
 
 .. _lists:
 
@@ -340,6 +343,12 @@ suspended.  The only difference is that a generator function cannot control
 where should the execution continue after it yields; the control is always
 transfered to the generator's caller.
 
+The :keyword:`yield` statement is allowed in the :keyword:`try` clause of a
+:keyword:`try` ...  :keyword:`finally` construct.  If the generator is not
+resumed before it is finalized (by reaching a zero reference count or by being
+garbage collected), the generator-iterator's :meth:`close` method will be
+called, allowing any pending :keyword:`finally` clauses to execute.
+
 .. index:: object: generator
 
 The following generator's methods can be used to control the execution of a
@@ -428,6 +437,9 @@ generator functions::
 
 .. seealso::
 
+   :pep:`0255` - Simple Generators
+      The proposal for adding generators and the :keyword:`yield` statement to Python.
+
    :pep:`0342` - Coroutines via Enhanced Generators
       The proposal to enhance the API and syntax of generators, making them
       usable as simple coroutines.

Doc/reference/toplevel_components.rst

@@ -53,9 +53,9 @@ a complete program; each statement is executed in the namespace of
 
 Under Unix, a complete program can be passed to the interpreter in three forms:
 with the :option:`-c` *string* command line option, as a file passed as the
-first command line argument, or as standard input. If the file or standard input
-is a tty device, the interpreter enters interactive mode; otherwise, it executes
-the file as a complete program.
+first command line argument, or as standard input.  If the file or standard
+input is a tty device, the interpreter enters interactive mode; otherwise, it
+executes the file as a complete program.
 
 
 .. _file-input: