Docs: Add notes about file format support

doc/fileformats.html

@@ -71,6 +71,10 @@ <h1 class=sitename>Sector Data File Formats</h1>
 <section id="trader">
 <h2>TRADER Format</h2>
 
+<p class=highlight>
+    NOTE: This format is documented for posterity; it is not supported by the site's tools.
+</p>
+
 <p>
 The original electronic format for sector data was defined
 by Marc Miller in <em>"Electronically Exploring the Traveller Universe"</em>
@@ -752,6 +756,10 @@ <h2>T5 Tab Delimited Format</h2>
 <section id="t5col">
 <h2>T5 Column Delimited Format</h2>
 
+<p class=highlight>
+  NOTE: If not explicitly specified by request headers, the site's tools only auto-detect this format if the <code>{Ix}</code>, <code>(Ex)</code> and <code>[Cx]</code> headers are present. Otherwise another format will be inferred. Include those fields in the header (even if the content is blank) to use this format.
+</p>
+
 <p>
 Although the tab-delimited format is the most convenient for interchange
 it is difficult for humans to read. This document establishes an extensible,

site.css

@@ -130,6 +130,10 @@ td.number, th.number {
   font-family: 'Arial';
 }
 
+.highlight {
+  color: #ff2000;
+}
+
 /* Code Samples and Parameter Definitions */
 
 dl.params {