Fix some spelling errors

Documentation/Demo/README.md

@@ -27,7 +27,7 @@ Demo Application
 
     Players defines read and write operations on the players database.
 
-    It exposes a [publisher](../../Sources/GRDBCombine/DatabasePublishersValue.swift) of HallOfFame, that changes everytime the database is modified.
+    It exposes a [publisher](../../Sources/GRDBCombine/DatabasePublishersValue.swift) of HallOfFame, that changes every time the database is modified.
 
     ```swift
     struct HallOfFame {

README.md

@@ -148,7 +148,7 @@ The fetched value is published on the main queue, unless you provide a specific
 
 #### `DatabaseWriter.writePublisher(receiveOn:updates:)`
 
-This method returns a publisher that completes after database updates have been succesfully executed inside a database transaction.
+This method returns a publisher that completes after database updates have been successfully executed inside a database transaction.
 
 ```swift
 // AnyPublisher<Void, Error>
@@ -172,7 +172,7 @@ When you use a [database pool], and your app executes some database updates foll
 
 #### `DatabaseWriter.writePublisher(receiveOn:updates:thenRead:)`
 
-This method returns a publisher that completes after database updates have been succesfully executed inside a database transaction, and values have been subsequently fetched:
+This method returns a publisher that completes after database updates have been successfully executed inside a database transaction, and values have been subsequently fetched:
 
 ```swift
 // AnyPublisher<Int, Error>