attempt to fix a 404

capitalization seems to matter; PREVIEW was all-caps in the preserved July 11th, 2021 printing of the AT map

mc/atmaps.html

@@ -11,7 +11,7 @@ <h1>Graphics preserved by the Alantown Historical Society</h1>
 <h2>Network diagrams</h2>
 <p>The three most recent iterations are provided, both in varying degrees of progress. Their gestalt snapshots the complete and incomplete routes in the last month or so before the Alantown iteration of the server lost stability and went down permanently on August 22nd, 2021.</p>
 <p><a href="atmaps/AT City Map EFF6JUL21.pdf">Effective July 6th, 2021</a></p>
-<p><a href="atmaps/AT City Map preview EFF11JUL21.pdf">"Preview" of edition intended to take effect July 11th, 2021</a>. Beginnings of Grimbleton System expansions and streetcar re-realignments</p>
+<p><a href="atmaps/AT City Map PREVIEW EFF11JUL21.pdf">"Preview" of edition intended to take effect July 11th, 2021</a>. Beginnings of Grimbleton System expansions and streetcar re-realignments</p>
 <p><a href="atmaps/AT City Map autosave 30JUL21.pdf">Rendered from an Inkscape autosave dated July 30th, 2021</a>. Further iterations of the above, but naming and interchange boxes around the "Underway" underground concourses were broken up for editing.</p>
 <h2>Individual graphics</h2>
 <p>Newest generation (before server shutdown) of <a href="atmaps/stops">boards at stops</a> on the Alantown Streetcar (ASC) and rebranded Grimbleton Stadtbahn (GS; boards feature German-style U rebrand)</p>