contrib/win32: format file names and env vars with <tt>

contrib/win32/ReadMe.html

@@ -65,8 +65,8 b' hg'
     <h4>Default editor</h4>
     <p>
       The default editor for commit messages is 'notepad'. You can set
-      the EDITOR (or HGEDITOR) environment variable to specify your
-      preference or set it in mercurial.ini:
+      the <tt>EDITOR</tt> (or <tt>HGEDITOR</tt>) environment variable
+      to specify your preference or set it in <tt>mercurial.ini</tt>:
     </p>
     <pre>
 [ui]
@@ -82,8 +82,8 b' editor = whatever'
 
     <p>
       By default, Mercurial will use the merge program defined by the
-      HGMERGE environment variable, or uses the one defined in the
-      mercurial.ini file. (see <a
+      <tt>HGMERGE</tt> environment variable, or uses the one defined
+      in the <tt>mercurial.ini</tt> file. (see <a
       href="http://www.selenic.com/mercurial/wiki/index.cgi/MergeProgram">MergeProgram</a>
       on the Mercurial Wiki for more information)
     </p>