Fix typo and variable names (#3649)

## Motivation

There was a small typo in one of the error enums, and also some variable names that sounded confusing to me

## Proposal

Fix typo and improve variable names a bit

## Test Plan

CI

## Release Plan

- Nothing to do / These changes follow the usual release cycle.

Author: ndr-ds

linera-views/src/backends/dual.rs

@@ -321,21 +321,21 @@ where
     }
 
     async fn create(config: &Self::Config, namespace: &str) -> Result<(), Self::Error> {
-        let test1 = S1::exists(&config.first_config, namespace)
+        let exists1 = S1::exists(&config.first_config, namespace)
             .await
             .map_err(DualStoreError::First)?;
-        let test2 = S2::exists(&config.second_config, namespace)
+        let exists2 = S2::exists(&config.second_config, namespace)
             .await
             .map_err(DualStoreError::Second)?;
-        if test1 && test2 {
+        if exists1 && exists2 {
             return Err(DualStoreError::StoreAlreadyExist);
         }
-        if !test1 {
+        if !exists1 {
             S1::create(&config.first_config, namespace)
                 .await
                 .map_err(DualStoreError::First)?;
         }
-        if !test2 {
+        if !exists2 {
             S2::create(&config.second_config, namespace)
                 .await
                 .map_err(DualStoreError::Second)?;

linera-views/src/backends/rocks_db.rs

@@ -523,7 +523,7 @@ impl AdminKeyValueStore for RocksDbStoreInternal {
         let mut path_buf = config.path_with_guard.path_buf.clone();
         path_buf.push(namespace);
         if std::path::Path::exists(&path_buf) {
-            return Err(RocksDbStoreInternalError::StoreAlreadyExist);
+            return Err(RocksDbStoreInternalError::StoreAlreadyExists);
         }
         std::fs::create_dir_all(path_buf)?;
         Ok(())
@@ -562,9 +562,9 @@ impl TestKeyValueStore for RocksDbStoreInternal {
 /// The error type for [`RocksDbStoreInternal`]
 #[derive(Error, Debug)]
 pub enum RocksDbStoreInternalError {
-    /// Already existing storage
-    #[error("Already existing storag")]
-    StoreAlreadyExist,
+    /// Store already exists
+    #[error("Store already exists")]
+    StoreAlreadyExists,
 
     /// Tokio join error in RocksDB.
     #[error("tokio join error: {0}")]