Fix: types fields privacy (make fields of some types public)

The typos were found with `grep`:
```text
; grep -r -P "^    \w{2,}: .+, *$" ./src/types/*
./src/types/dice.rs:    emoji: DiceEmoji,
./src/types/dice.rs:    value: i32,
./src/types/keyboard_button.rs:    contact: Option<True>,
./src/types/keyboard_button.rs:    location: Option<True>,
./src/types/keyboard_button.rs:    poll: Option<KeyboardButtonPollType>,
./src/types/message.rs:    message_auto_delete_timer_changed: MessageAutoDeleteTimerChanged,
./src/types/passport_element_error.rs:    message: String,
./src/types/passport_element_error.rs:    kind: PassportElementErrorKind,
./src/types/sticker_set.rs:    thumb: Option<PhotoSize>,
```

`src/types/keyboard_button.rs` can be ignored since in just contains private
helper structure.

Fields made public:
- `Dice::{emoji, value}`
- `MessageMessageAutoDeleteTimerChanged::message_auto_delete_timer_changed`
- `PassportElementError::{message, kind}`
- `StickerSet::thumb`

CHANGELOG.md

@@ -7,6 +7,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [unreleased]
 
+### Fixed 
+
+- Types fields privacy (make fields of some types public) ([#68][pr68])
+  - `Dice::{emoji, value}`
+  - `MessageMessageAutoDeleteTimerChanged::message_auto_delete_timer_changed`
+  - `PassportElementError::{message, kind}`
+  - `StickerSet::thumb`
+
+[pr68]: https://github.com/teloxide/teloxide-core/pull/68
+
 ## [0.2.0] - 2020-03-16
 
 ### Changed

src/types/dice.rs

@@ -7,7 +7,7 @@ use crate::types::DiceEmoji;
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub struct Dice {
     /// Emoji on which the dice throw animation is based.
-    emoji: DiceEmoji,
+    pub emoji: DiceEmoji,
 
     /// Value of the dice.
     ///
@@ -17,5 +17,5 @@ pub struct Dice {
     /// [`DiceEmoji::Dice`]: crate::types::DiceEmoji::Dice
     /// [`DiceEmoji::Darts`]:crate::types::DiceEmoji::Darts
     /// [`DiceEmoji::Basketball`]:crate::types::DiceEmoji::Basketball
-    value: i32,
+    pub value: i32,
 }

src/types/message.rs

@@ -151,7 +151,7 @@ pub struct MessageChannelChatCreated {
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub struct MessageMessageAutoDeleteTimerChanged {
     /// Service message: auto-delete timer settings changed in the chat.
-    message_auto_delete_timer_changed: MessageAutoDeleteTimerChanged,
+    pub message_auto_delete_timer_changed: MessageAutoDeleteTimerChanged,
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]

src/types/passport_element_error.rs

@@ -7,10 +7,10 @@ use serde::{Deserialize, Serialize};
 #[derive(Clone, Debug, Hash, Eq, PartialEq, Serialize, Deserialize)]
 pub struct PassportElementError {
     /// Error message.
-    message: String,
+    pub message: String,
 
     #[serde(flatten)]
-    kind: PassportElementErrorKind,
+    pub kind: PassportElementErrorKind,
 }
 
 impl PassportElementError {

src/types/sticker_set.rs

@@ -25,5 +25,5 @@ pub struct StickerSet {
     pub stickers: Vec<Sticker>,
 
     /// Sticker set thumbnail in the .WEBP or .TGS format.
-    thumb: Option<PhotoSize>,
+    pub thumb: Option<PhotoSize>,
 }