Fix two code snippets in manual

We need to single quote these to avoid template-toolkit trying to
interpret `$`.

compiler/snowman.tt

@@ -803,14 +803,14 @@ It is these numeric values of <B><I>c</I></B> and <B><I>l</I></B> which are acce
 <DL>
 <DT>[% highlight_inline("setmark X") %]
     <DD>sets &nbsp;<code>X</code>&nbsp; to the current value of <B><I>c</I></B>, where &nbsp;<code>X</code>&nbsp; is an integer variable.
-    It's equivalent to: [% highlight_inline("$X = cursor") %]
+    It's equivalent to: [% highlight_inline('$X = cursor') %]
 
 <DT>[% highlight_inline("tomark AE") %]
     <DD>moves <B><I>c</I></B> forward to the position given by AE,
 
 <DT>[% highlight_inline("atmark AE") %]
     <DD>tests if <B><I>c</I></B> is at position AE (<B><I>t</I></B> or <B><I>f</I></B> signal).
-    It's equivalent to: [% highlight_inline("$(cursor == AE)") %]
+    It's equivalent to: [% highlight_inline('$(cursor == AE)') %]
 </DL>
 
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