Update performance.md
Even though I just proofread this file, I noticed one more thing that needed correcting, which I fixed. The word "genereated" had to be corrected to "generated". My apologies for missing this on the initial check.
diff --git a/docs/performance.md b/docs/performance.md
index 6bb0235..8734c70 100644
--- a/docs/performance.md
+++ b/docs/performance.md
@@ -13,7 +13,7 @@
com.google.protobuf.ByteString.
* **InputStream** - This is for parsing from an InputStream.
* **Python** - For Python, there are three types of Python protobuf for testing:
- * **C++-genereated-code** - This is for using C++ generated code of the
+ * **C++-generated-code** - This is for using C++ generated code of the
proto file as a dynamic linked library.
* **C++-reflection** - This is for using C++ reflection, for which there's no
generated code, but still using C++ protobuf library as a dynamic linked
