Change {\em ...} to \emph{...}; this seems to be the developing preference

throughout the manuals, and seems easier to read.

Doc/lib.tex

@@ -26,7 +26,7 @@ Python is an extensible, interpreted, object-oriented programming
 language.  It supports a wide range of applications, from simple text
 processing scripts to interactive WWW browsers.
 
-While the {\em Python Reference Manual} describes the exact syntax and
+While the \emph{Python Reference Manual} describes the exact syntax and
 semantics of the language, it does not describe the standard library
 that is distributed with the language, and which greatly enhances its
 immediate usability.  This library contains built-in modules (written
@@ -46,9 +46,9 @@ functions and exceptions, many of which are not or incompletely
 documented in the Reference Manual.
 
 This manual assumes basic knowledge about the Python language.  For an
-informal introduction to Python, see the {\em Python Tutorial}; the
+informal introduction to Python, see the \emph{Python Tutorial}; the
 Python Reference Manual remains the highest authority on syntactic and
-semantic questions.  Finally, the manual entitled {\em Extending and
+semantic questions.  Finally, the manual entitled \emph{Extending and
 Embedding the Python Interpreter} describes how to add new extensions
 to Python and how to embed it in other applications.
 

Doc/lib/lib.tex

@@ -26,7 +26,7 @@ Python is an extensible, interpreted, object-oriented programming
 language.  It supports a wide range of applications, from simple text
 processing scripts to interactive WWW browsers.
 
-While the {\em Python Reference Manual} describes the exact syntax and
+While the \emph{Python Reference Manual} describes the exact syntax and
 semantics of the language, it does not describe the standard library
 that is distributed with the language, and which greatly enhances its
 immediate usability.  This library contains built-in modules (written
@@ -46,9 +46,9 @@ functions and exceptions, many of which are not or incompletely
 documented in the Reference Manual.
 
 This manual assumes basic knowledge about the Python language.  For an
-informal introduction to Python, see the {\em Python Tutorial}; the
+informal introduction to Python, see the \emph{Python Tutorial}; the
 Python Reference Manual remains the highest authority on syntactic and
-semantic questions.  Finally, the manual entitled {\em Extending and
+semantic questions.  Finally, the manual entitled \emph{Extending and
 Embedding the Python Interpreter} describes how to add new extensions
 to Python and how to embed it in other applications.