Make all 'Unknown' variants hidden

We only have 'Unknown' variants in enums that are marked non-exhaustive.
As such, there really is no point in singling out and treating special
such variants: it does not matter if something is formally unknown by
the apca crate itself or just unknown by the client application, both
cases basically have to be treated similarly.
At the same time, many of said enums can be used in input positions,
where the Unknown variant simply has no place.
As such, this change marks this variant as hidden. Its main purpose,
thus, is to prevent potentially fatal (in a long running service)
deserialization failures in otherwise legitimate responses.

src/api/v2/account.rs

@@ -58,7 +58,8 @@ pub enum Status {
   /// Any other account status that we have not accounted for.
   ///
   /// Note that having any such status should be considered a bug.
-  #[serde(other)]
+  #[doc(hidden)]
+  #[serde(other, rename(serialize = "unknown"))]
   Unknown,
 }
 

src/api/v2/account_activities.rs

@@ -143,7 +143,8 @@ pub enum ActivityType {
   /// Any other activity type that we have not accounted for.
   ///
   /// Note that having any such type should be considered a bug.
-  #[serde(other)]
+  #[doc(hidden)]
+  #[serde(other, rename(serialize = "unknown"))]
   Unknown,
 }
 

src/api/v2/asset.rs

@@ -46,6 +46,7 @@ pub enum Class {
   ///
   /// Note that having any such unknown asset class should be considered
   /// a bug.
+  #[doc(hidden)]
   #[serde(other, rename(serialize = "unknown"))]
   Unknown,
 }
@@ -101,6 +102,7 @@ pub enum Status {
   ///
   /// Note that having any such unknown asset class should be considered
   /// a bug.
+  #[doc(hidden)]
   #[serde(other, rename(serialize = "unknown"))]
   Unknown,
 }
@@ -278,7 +280,8 @@ pub enum Exchange {
   ///
   /// Note that having any such unknown exchange should be considered a
   /// bug.
-  #[serde(other)]
+  #[doc(hidden)]
+  #[serde(other, rename(serialize = "unknown"))]
   Unknown,
 }
 

src/api/v2/order.rs

@@ -120,6 +120,7 @@ pub enum Status {
   /// Any other status that we have not accounted for.
   ///
   /// Note that having any such status should be considered a bug.
+  #[doc(hidden)]
   #[serde(other, rename(serialize = "unknown"))]
   Unknown,
 }

src/api/v2/updates.rs

@@ -104,6 +104,7 @@ pub enum OrderStatus {
   /// Any other status that we have not accounted for.
   ///
   /// Note that having any such status should be considered a bug.
+  #[doc(hidden)]
   #[serde(other, rename(serialize = "unknown"))]
   Unknown,
 }