Fix typo

Author: gjbex

source-code/performance/README.md

@@ -6,7 +6,7 @@ These are some resources about general performance considerations.
 ## What is it?
 
 1. `number_puzzle.ipynb`: jupyter notebbook solving a number puzzle
-   in a variety of ways, shwoing some aspects of performance
+   in a variety of ways, showing some aspects of performance
    optimization.
 1. `cellular_automata`: some illustrations of profiling and performance
    optimizations.