Bug: updated filenames + paths for special_edition (#64)

I noticed that a couple of the themes (pride, thanksgiving, and winter) weren't working after changing the `holiday` directory to `special_edition`. This just fixes that and updates the filenames as well.

special_edition/grafbase.yaml

@@ -1,6 +1,6 @@
 background: "#131313"
 background_image:
-  path: special_edition/grafbase.jpg
+  path: special_edition/grafbase_bg.jpg
 terminal_colors:
   normal:
     magenta: "#45b192"

special_edition/pride.yaml

@@ -1,6 +1,6 @@
 background_image:
   # background image author: Shikhiu Ing, Warp.dev
-  path: holiday/pride_bg.jpg
+  path: special_edition/pride_bg.jpg
   opacity: 47
 accent: "#ffffff"
 background: "#000000"

special_edition/thanksgiving.yaml

@@ -1,6 +1,6 @@
 background_image:
   # background image credit: https://unsplash.com/photos/ZwPuquZBnyM
-  path: holiday/thanksgiving_bg.jpg
+  path: special_edition/thanksgiving_bg.jpg
   opacity: 47
 accent: "#b3deef"
 background: "#282828"

special_edition/winter.yaml

@@ -2,7 +2,7 @@ accent: "#6587bf"
 background: "#fafafa"
 background_image:
   # background image credit: https://unsplash.com/photos/TD8CbG9-sMk
-  path: holiday/winter_bg.jpg
+  path: special_edition/winter_bg.jpg
   opacity: 47
 
 details: lighter