Fix typo (#468)

docs/_docs/20-fasterkv-basics.md

@@ -101,7 +101,7 @@ Apart from Key and Value, the IFunctions interface is defined on three additiona
 `IFunctions<>` encapsulates all callbacks made by FASTER back to the caller, which are described next:
 
 1. SingleReader and ConcurrentReader: These are used to read from the store values and copy them to Output. Single reader can assume that there are no concurrent operations on the record.
-2. SingleWriter and ConcurrentWriter: These are used to write values to the store, from a source value. Concurrent writer can assume that there are no concurrent operations on the record.
+2. SingleWriter and ConcurrentWriter: These are used to write values to the store, from a source value. Single writer can assume that there are no concurrent operations on the record.
 3. Completion callbacks: Called by FASTER when various operations complete after they have gone "pending" due to requiring IO.
 4. RMW Updaters: There are three updaters that the user specifies, InitialUpdater, InPlaceUpdater, and CopyUpdater. Together, they are used to implement the RMW operation.
 5. Locking: There is one property and two methods; if the SupportsLocking property returns true, then FASTER will call Lock and Unlock within a try/finally in the four concurrent callback methods: ConcurrentReader, ConcurrentWriter, ConcurrentDeleter (new in IAdvancedFunctions), and InPlaceUpdater. FunctionsBase illustrates the default implementation of Lock and Unlock as an exclusive lock using a bit in RecordInfo.