minor: document fixes

lib/mongo/connection.rb

@@ -210,11 +210,11 @@ module Mongo
     end
 
     # Sends a message to the database, waits for a response, and raises
-    # and exception if the operation has failed.
+    # an exception if the operation has failed.
     #
     # Takes a MongoDB opcode, +operation+, a message of class ByteBuffer,
     # +message+, the +db_name+, and an optional formatted +log_message+.
-    # Sends the message to the databse, adding the necessary headers.
+    # Sends the message to the database, adding the necessary headers.
     def send_message_with_safe_check(operation, message, db_name, log_message=nil)
       message_with_headers = add_message_headers(operation, message)
       message_with_check   = last_error_message(db_name)

lib/mongo/db.rb

@@ -132,7 +132,7 @@ module Mongo
       names.map {|name| name.sub(@name + '.', '')}
     end
 
-    # Retruns an array of Collection instances, one for each collection in this
+    # Retuns an array of Collection instances, one for each collection in this
     # database.
     def collections
       collection_names.map do |collection_name|

lib/mongo/errors.rb

@@ -45,7 +45,7 @@ module Mongo
   # Raised when a database operation fails.
   class OperationFailure < MongoDBError; end
 
-  # Raised when a database operation fails.
+  # Raised when a connection operation fails.
   class ConnectionFailure < MongoDBError; end
 
   # Raised when a client attempts to perform an invalid operation.