Don't use \samp when \code is better.

Consistently use ' instead of ":  this conforms to my unofficial stance that
constants should be presented using the repr() whenever it makes sense.  This
isn't because I think repr() is the greatest thing since spam, just that it's
an easy to adopt consistency standard.  (It also holds no new surprises!)
diff --git a/Doc/lib/libprofile.tex b/Doc/lib/libprofile.tex
index 8aa5477..758944d 100644
--- a/Doc/lib/libprofile.tex
+++ b/Doc/lib/libprofile.tex
@@ -110,7 +110,7 @@
 
 \begin{verbatim}
 import profile
-profile.run("foo()")
+profile.run('foo()')
 \end{verbatim}
 %
 The above action would cause \samp{foo()} to be run, and a series of
@@ -122,7 +122,7 @@
 
 \begin{verbatim}
 import profile
-profile.run("foo()", 'fooprof')
+profile.run('foo()', 'fooprof')
 \end{verbatim}
 %
 The file \file{profile.py} can also be invoked as
@@ -388,8 +388,8 @@
 \begin{methoddesc}{sort_stats}{key\optional{, ...}}
 This method modifies the \class{Stats} object by sorting it according
 to the supplied criteria.  The argument is typically a string
-identifying the basis of a sort (example: \code{"time"} or
-\code{"name"}).
+identifying the basis of a sort (example: \code{'time'} or
+\code{'name'}).
 
 When more than one key is provided, then additional keys are used as
 secondary criteria when the there is equality in all keys selected
@@ -417,18 +417,18 @@
 Note that all sorts on statistics are in descending order (placing
 most time consuming items first), where as name, file, and line number
 searches are in ascending order (i.e., alphabetical). The subtle
-distinction between \code{"nfl"} and \code{"stdname"} is that the
+distinction between \code{'nfl'} and \code{'stdname'} is that the
 standard name is a sort of the name as printed, which means that the
 embedded line numbers get compared in an odd way.  For example, lines
 3, 20, and 40 would (if the file names were the same) appear in the
-string order 20, 3 and 40.  In contrast, \code{"nfl"} does a numeric
-compare of the line numbers.  In fact, \code{sort_stats("nfl")} is the
-same as \code{sort_stats("name", "file", "line")}.
+string order 20, 3 and 40.  In contrast, \code{'nfl'} does a numeric
+compare of the line numbers.  In fact, \code{sort_stats('nfl')} is the
+same as \code{sort_stats('name', 'file', 'line')}.
 
 For compatibility with the old profiler, the numeric arguments
-\samp{-1}, \samp{0}, \samp{1}, and \samp{2} are permitted.  They are
-interpreted as \code{"stdname"}, \code{"calls"}, \code{"time"}, and
-\code{"cumulative"} respectively.  If this old style format (numeric)
+\code{-1}, \code{0}, \code{1}, and \code{2} are permitted.  They are
+interpreted as \code{'stdname'}, \code{'calls'}, \code{'time'}, and
+\code{'cumulative'} respectively.  If this old style format (numeric)
 is used, only one sort key (the numeric key) will be used, and
 additional arguments will be silently ignored.
 \end{methoddesc}
@@ -461,7 +461,7 @@
 provided, then they are applied sequentially.  For example:
 
 \begin{verbatim}
-print_stats(.1, "foo:")
+print_stats(.1, 'foo:')
 \end{verbatim}
 
 would first limit the printing to first 10\% of list, and then only
@@ -469,7 +469,7 @@
 contrast, the command:
 
 \begin{verbatim}
-print_stats("foo:", .1)
+print_stats('foo:', .1)
 \end{verbatim}
 
 would limit the list to all functions having file names \samp{.*foo:},