fixup! Document error GHC-05380

Author: jorisburgers

message-index/messages/GHC-05380/index.md

@@ -10,6 +10,7 @@ constructors, you should use `data` instead of `newtype`.
 
 The reason that you need exactly one constructor is that `newtype` constructors
 are removed at runtime.
-So during runtime, if you define `newtype Age = Age Int`, `Age` is the same as `Int`.
-Only during the compilation phase, will the `Age` and `Int` types be different.
-If we allow multiple constructors for a newtype, there would be no way to distinguish them during execution.
+For example, if you define `newtype Age = Age Int`, the bits in memory that represent
+an `Age` are identical to those that would represent the `Int` in the constructor.
+The `Age` and `Int` types are distinguished only at compile time.
+If types defined with `newtype` could have multiple constructors, there would be no way to distinguish them during execution.

message-index/messages/GHC-05380/more-than-1-constructor/index.md

@@ -14,5 +14,5 @@ Main.hs:1:1: error: [GHC-05380]
 ```
 ## Explanation
 
-A newtype constructor can only have a single constructor. It is not allowed to have multiple
-constructors when defining a newtype.
+A `newtype` constructor can only have a single constructor.
+It is not allowed to have multiple constructors when defining a `newtype`.

message-index/messages/GHC-05380/zero-constructors/index.md

@@ -14,7 +14,7 @@ Main.hs:1:1: error: [GHC-05380]
 
 ## Explanation
 
-A `newtype` constructor does need to have a single constructor. It is not allowed to
-have a newtype without a constructor. It is allowed to have a `data` type without a
-constructor, so in order to fix this, you need to come up with a constructor for the newtype
-or change the `newtype` keyword to a `data` keyword.
+A `newtype` definition is required to have exactly one constructor, so constructorless `newtype`s are not allowed.
+Datatypes defined using `data` are allowed to be constructorless,
+so this problem can be fixed either by adding a constructor to the `newtype`
+or by changing the `newtype` keyword to a `data` keyword.