docs: Fix a typo

refs: #4232

Change-Id: Ibe4d07fb459ba5052a58cbe6c78cdaa8a2cd423d
diff --git a/docs/INSTALL.rst b/docs/INSTALL.rst
index 5d94e35..428c064 100644
--- a/docs/INSTALL.rst
+++ b/docs/INSTALL.rst
@@ -274,7 +274,7 @@
     ./waf sphinx
 
     # Only API docs in `build/docs/doxygen`
-    ./waf doxgyen
+    ./waf doxygen
 
 Manpages are automatically created and installed during the normal build
 process (e.g., during ``./waf`` and ``./waf install``), if