Fix case for 'Unix'

Doc/lib/libcsv.tex

@@ -76,7 +76,7 @@ If literal newlines are important within a field, users need to read their
 file in a way that preserves the newlines. The behavior before 2.5 would
 introduce spurious characters into quoted fields, with no way for the user
 to control that behavior. The previous behavior caused considerable
-problems, particularly on platforms that did not use the unix line ending
+problems, particularly on platforms that did not use the Unix line ending
 conventions, or with files that originated on those platforms --- users were
 finding mysterious newlines where they didn't expect them]{2.5}
 

Doc/lib/tkinter.tex

@@ -319,7 +319,7 @@ the name of a widget.
 \item[\var{options} ]
 configure the widget's appearance and in some cases, its
 behavior.  The options come in the form of a list of flags and values.
-Flags are proceeded by a `-', like unix shell command flags, and
+Flags are proceeded by a `-', like Unix shell command flags, and
 values are put in quotes if they are more than one word.
 \end{description}