Update the first two parts of the reference manual for Py3k,

mainly concerning PEPs 3131 and 3120.

Doc/documenting/index.rst

@@ -27,6 +27,7 @@ are more than welcome as well.
    style.rst
    rest.rst
    markup.rst
+   fromlatex.rst
    sphinx.rst
 
 .. XXX add credits, thanks etc.

Doc/reference/introduction.rst

@@ -22,11 +22,12 @@ language, maybe you could volunteer your time --- or invent a cloning machine
 
 It is dangerous to add too many implementation details to a language reference
 document --- the implementation may change, and other implementations of the
-same language may work differently.  On the other hand, there is currently only
-one Python implementation in widespread use (although alternate implementations
-exist), and its particular quirks are sometimes worth being mentioned,
-especially where the implementation imposes additional limitations.  Therefore,
-you'll find short "implementation notes" sprinkled throughout the text.
+same language may work differently.  On the other hand, CPython is the one
+Python implementation in widespread use (although alternate implementations
+continue to gain support), and its particular quirks are sometimes worth being
+mentioned, especially where the implementation imposes additional limitations.
+Therefore, you'll find short "implementation notes" sprinkled throughout the
+text.
 
 Every Python implementation comes with a number of built-in and standard
 modules.  These are documented in :ref:`library-index`.  A few built-in modules
@@ -88,11 +89,7 @@ implementation you're using.
 Notation
 ========
 
-.. index::
-   single: BNF
-   single: grammar
-   single: syntax
-   single: notation
+.. index:: BNF, grammar, syntax, notation
 
 The descriptions of lexical analysis and syntax use a modified BNF grammar
 notation.  This uses the following style of definition:
@@ -118,9 +115,7 @@ meaningful to separate tokens. Rules are normally contained on a single line;
 rules with many alternatives may be formatted alternatively with each line after
 the first beginning with a vertical bar.
 
-.. index::
-   single: lexical definitions
-   single: ASCII@ASCII
+.. index:: lexical definitions, ASCII
 
 In lexical definitions (as the example above), two more conventions are used:
 Two literal characters separated by three dots mean a choice of any single