fix(audio-reader): valid doctype — page loaded in quirks mode

audio_reader.templ was the only template emitting <!DOCTYPE html/>
(trailing slash is a parse error), which put the audio player page in
quirks mode — document.compatMode was BackCompat while every other
page is CSS1Compat. Quirks layout rules are a standing hazard for the
player's h-screen/flex page even where it happens to render. Drop the
slash.

templates/audio_reader.templ

@@ -10,7 +10,7 @@ package templates
 import "fmt"
 
 templ AudioReader(user User, metadata ReaderMetadata) {
-	<!DOCTYPE html/>
+	<!DOCTYPE html>
 	<html lang="en">
 		<head>
 			<title>{ "Listening · " + metadata.Title } · Bookhoard</title>

templates/audio_reader_templ.go

@@ -38,7 +38,7 @@ func AudioReader(user User, metadata ReaderMetadata) templ.Component {
 			templ_7745c5c3_Var1 = templ.NopComponent
 		}
 		ctx = templ.ClearChildren(ctx)
-		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 1, "<!doctype html/><html lang=\"en\"><head><title>")
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 1, "<!doctype html><html lang=\"en\"><head><title>")
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}