enable unreachable_pub lint

This causes some other lints to start firing too (which is good), but
I'm going to fix them in follow-up commits to keep things organized.

src/service/key_backups.rs

@@ -1,5 +1,5 @@
 mod data;
-pub use data::Data;
+pub(crate) use data::Data;
 
 use crate::Result;
 use ruma::{
@@ -9,12 +9,12 @@ use ruma::{
 };
 use std::collections::BTreeMap;
 
-pub struct Service {
-    pub db: &'static dyn Data,
+pub(crate) struct Service {
+    pub(crate) db: &'static dyn Data,
 }
 
 impl Service {
-    pub fn create_backup(
+    pub(crate) fn create_backup(
         &self,
         user_id: &UserId,
         backup_metadata: &Raw<BackupAlgorithm>,
@@ -22,11 +22,11 @@ impl Service {
         self.db.create_backup(user_id, backup_metadata)
     }
 
-    pub fn delete_backup(&self, user_id: &UserId, version: &str) -> Result<()> {
+    pub(crate) fn delete_backup(&self, user_id: &UserId, version: &str) -> Result<()> {
         self.db.delete_backup(user_id, version)
     }
 
-    pub fn update_backup(
+    pub(crate) fn update_backup(
         &self,
         user_id: &UserId,
         version: &str,
@@ -35,18 +35,18 @@ impl Service {
         self.db.update_backup(user_id, version, backup_metadata)
     }
 
-    pub fn get_latest_backup_version(&self, user_id: &UserId) -> Result<Option<String>> {
+    pub(crate) fn get_latest_backup_version(&self, user_id: &UserId) -> Result<Option<String>> {
         self.db.get_latest_backup_version(user_id)
     }
 
-    pub fn get_latest_backup(
+    pub(crate) fn get_latest_backup(
         &self,
         user_id: &UserId,
     ) -> Result<Option<(String, Raw<BackupAlgorithm>)>> {
         self.db.get_latest_backup(user_id)
     }
 
-    pub fn get_backup(
+    pub(crate) fn get_backup(
         &self,
         user_id: &UserId,
         version: &str,
@@ -54,7 +54,7 @@ impl Service {
         self.db.get_backup(user_id, version)
     }
 
-    pub fn add_key(
+    pub(crate) fn add_key(
         &self,
         user_id: &UserId,
         version: &str,
@@ -66,15 +66,15 @@ impl Service {
             .add_key(user_id, version, room_id, session_id, key_data)
     }
 
-    pub fn count_keys(&self, user_id: &UserId, version: &str) -> Result<usize> {
+    pub(crate) fn count_keys(&self, user_id: &UserId, version: &str) -> Result<usize> {
         self.db.count_keys(user_id, version)
     }
 
-    pub fn get_etag(&self, user_id: &UserId, version: &str) -> Result<String> {
+    pub(crate) fn get_etag(&self, user_id: &UserId, version: &str) -> Result<String> {
         self.db.get_etag(user_id, version)
     }
 
-    pub fn get_all(
+    pub(crate) fn get_all(
         &self,
         user_id: &UserId,
         version: &str,
@@ -82,7 +82,7 @@ impl Service {
         self.db.get_all(user_id, version)
     }
 
-    pub fn get_room(
+    pub(crate) fn get_room(
         &self,
         user_id: &UserId,
         version: &str,
@@ -91,7 +91,7 @@ impl Service {
         self.db.get_room(user_id, version, room_id)
     }
 
-    pub fn get_session(
+    pub(crate) fn get_session(
         &self,
         user_id: &UserId,
         version: &str,
@@ -101,11 +101,11 @@ impl Service {
         self.db.get_session(user_id, version, room_id, session_id)
     }
 
-    pub fn delete_all_keys(&self, user_id: &UserId, version: &str) -> Result<()> {
+    pub(crate) fn delete_all_keys(&self, user_id: &UserId, version: &str) -> Result<()> {
         self.db.delete_all_keys(user_id, version)
     }
 
-    pub fn delete_room_keys(
+    pub(crate) fn delete_room_keys(
         &self,
         user_id: &UserId,
         version: &str,
@@ -114,7 +114,7 @@ impl Service {
         self.db.delete_room_keys(user_id, version, room_id)
     }
 
-    pub fn delete_room_key(
+    pub(crate) fn delete_room_key(
         &self,
         user_id: &UserId,
         version: &str,