Fix typo in library doc title

Change-Id: I2b8ead582226046903116eac6a2594370017d036
diff --git a/doc/source/library.rst b/doc/source/library.rst
index 24ead08..8b263f2 100644
--- a/doc/source/library.rst
+++ b/doc/source/library.rst
@@ -1,6 +1,6 @@
 .. _library:
 
-Tempest Library Doucmentation
+Tempest Library Documentation
 =============================
 
 Tempest provides a stable library interface that provides external tools or