Restore chapter description alpha (#8345)

Restore "Darken the description colors"

Restores #3858, with new values based on current standards (0.78f rather than 0.62f)

I wanted to accomplish this without having to call a const, but that felt like a logical solution as well

Of course, if you got cleaner methods do tell, thanks

(cherry picked from commit 04d2a3399b)

app/src/main/java/eu/kanade/presentation/util/Constants.kt

@@ -12,3 +12,4 @@ val verticalPadding = vertical
 val topPaddingValues = PaddingValues(top = vertical)
 
 const val ReadItemAlpha = .38f
+const val SecondaryItemAlpha = .78f

app/src/main/java/eu/kanade/presentation/util/Modifier.kt

@@ -29,7 +29,7 @@ fun Modifier.selectedBackground(isSelected: Boolean): Modifier = composed {
     }
 }
 
-fun Modifier.secondaryItemAlpha(): Modifier = this.alpha(.78f)
+fun Modifier.secondaryItemAlpha(): Modifier = this.alpha(SecondaryItemAlpha)
 
 fun Modifier.clickableNoIndication(
     onLongClick: (() -> Unit)? = null,