[Editorial] Fix apparent printing error, soon -> so on

src/epub/text/bexar-scrip-no-2692.xhtml

@@ -29,7 +29,7 @@
 			<p>“Signature a forgery.”</p>
 			<p>“Patent refused⁠—duplicate patented elsewhere.”</p>
 			<p>“Field notes forged.”</p>
-			<p>“Certificates stolen from office”⁠—and soon ad infinitum.</p>
+			<p>“Certificates stolen from office”⁠—and so on ad infinitum.</p>
 			<p>The record books, spread upon long tables, in the big room upstairs, are open to the examination of all. Open them, and you will find the dark and greasy finger prints of half a century’s handling. The quick hand of the land grabber has fluttered the leaves a million times; the damp clutch of the perturbed tiller of the soil has left traces of his calling on the ragged leaves.</p>
 			<p>Interest centres in the file room.</p>
 			<p>This is a large room, built as a vault, fireproof, and entered by but a single door.</p>