Everywhere: Prefer {:#x} over 0x{:x} in format strings

The former automatically adapts the prefix to binary and octal
output, and is what we already use in the majority of cases.

Patch generated by:

    rg -l '0x\{' | xargs sed -i '' -e 's/0x{:/{:#/'

I ran it 4 times (until it stopped changing things) since each
invocation only converted one instance per line.

No behavior change.

Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp

@@ -1171,7 +1171,7 @@ static ErrorOr<void> read_colour_encoding(JPEGStream& stream, [[maybe_unused]] J
         context.color_transform = ColorTransform::YCCK;
         break;
     default:
-        dbgln("0x{:x} is not a specified transform flag value, ignoring", color_transform);
+        dbgln("{:#x} is not a specified transform flag value, ignoring", color_transform);
     }
 
     return {};