Update a condition in shortcodes

It turns out that my test was bad, and the condition in the previous commit was not enough

layouts/shortcodes/box.html

 <div class="box">
-  <picture class="img-fluid"> {{ $darkname := print (substr (.Get "src") 0 -4) "-dark.png" }} {{ if or (fileExists (print "static/" .Page.File.Dir .Page.File.BaseFileName "/" $darkname)) (fileExists $darkname) }} <source srcset="{{ .Page.Permalink }}{{ $darkname }}" media="(prefers-color-scheme: dark)"> {{ end }}
+  <picture class="img-fluid"> {{ $darkname := print (substr (.Get "src") 0 -4) "-dark.png" }} {{ if or (fileExists (print "static/" .Page.File.Dir .Page.File.BaseFileName "/" $darkname)) (fileExists (print "/" .Page.File.Dir $darkname)) }} <source srcset="{{ .Page.Permalink }}{{ $darkname }}" media="(prefers-color-scheme: dark)"> {{ end }}
     <img src="{{ .Page.Permalink }}{{ .Get "src" }}" class="img-fluid" alt="{{ .Get "alt" }}" loading="lazy" />
   </picture>
 </div>

layouts/shortcodes/feature.html

@@ -3,7 +3,7 @@
     {{ .Inner | $.Page.RenderString }}
   </div>
   <div>
-    <picture class="img-fluid"> {{ $darkname := print (substr (.Get "src") 0 -4) "-dark.png" }} {{ if or (fileExists (print "static/" .Page.File.Dir .Page.File.BaseFileName "/" $darkname)) (fileExists $darkname) }} <source srcset="{{ .Page.Permalink }}{{ $darkname }}" media="(prefers-color-scheme: dark)"> {{ end }}
+    <picture class="img-fluid"> {{ $darkname := print (substr (.Get "src") 0 -4) "-dark.png" }} {{ if or (fileExists (print "static/" .Page.File.Dir .Page.File.BaseFileName "/" $darkname)) (fileExists (print "/" .Page.File.Dir $darkname)) }} <source srcset="{{ .Page.Permalink }}{{ $darkname }}" media="(prefers-color-scheme: dark)"> {{ end }}
       <img src="{{ .Page.Permalink }}{{ .Get "src" }}" class="img-fluid" alt="{{ .Get "alt" }}" loading="lazy" />
     </picture>
   </div>

layouts/shortcodes/img.html

@@ -9,7 +9,7 @@
       {{ end }}
       <img src="{{ .Get "src" }}" class="img-fluid" alt="{{ .Get "alt" }}" loading="lazy" />
     {{ else }}
-      {{ if or (fileExists (print "static/" .Page.File.Dir .Page.File.BaseFileName "/" $darkname)) (fileExists $darkname) }}
+      {{ if or (fileExists (print "static/" .Page.File.Dir .Page.File.BaseFileName "/" $darkname)) (fileExists (print "/" .Page.File.Dir $darkname)) }}
       <source srcset="{{ .Page.Permalink }}{{ $darkname }}" media="(prefers-color-scheme: dark)">
       {{ end }}
       <img src="{{ .Page.Permalink }}{{ .Get "src" }}" class="img-fluid" alt="{{ .Get "alt" }}" loading="lazy" />