Prettier 2: Electric Boogaloo (#6113)

# Description of Changes
When I added Prettier formatting in #6052, my aim was to use just the
default settings in Prettier. Turns out, Prettier looks _really hard_
for any config files if it's not explicitly given one, which means that
if a developer has some sort of Prettier config file lying around on
their system, Prettier might find it and use it. Also, Prettier changes
its defaults based on stuff in `.editorconfig` without any good way of
disabling that behaviour explicitly in its config file.

To solve both of these issues, I've introduced a `.prettierrc` file
which sets Prettier's defaults explicitly, and then reformatted all our
code _again_ in Prettier's actual default settings. This should achieve
the aim of #6052 and remove the possibility for it breaking on different
dev computers.

frontend/src/core/components/shared/FilePreview.tsx

@@ -68,7 +68,12 @@ const FilePreview: React.FC<FilePreviewProps> = ({
 
   // Build the component composition
   let content = (
-    <DocumentThumbnail file={file} thumbnail={thumbnail} style={animationStyle} onClick={() => onFileClick?.(file)} />
+    <DocumentThumbnail
+      file={file}
+      thumbnail={thumbnail}
+      style={animationStyle}
+      onClick={() => onFileClick?.(file)}
+    />
   );
 
   // Wrap with hover overlay if needed
@@ -84,7 +89,11 @@ const FilePreview: React.FC<FilePreviewProps> = ({
   // Wrap with navigation if needed
   if (showNavigation && hasMultipleFiles && onPrevious && onNext) {
     content = (
-      <NavigationArrows onPrevious={onPrevious} onNext={onNext} disabled={isAnimating}>
+      <NavigationArrows
+        onPrevious={onPrevious}
+        onNext={onNext}
+        disabled={isAnimating}
+      >
         {content}
       </NavigationArrows>
     );