fix broken link to documentation

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@2222 44740490-163a-0410-bde0-09ae8108e29a

docs/simplesamlphp-sp.txt

@@ -141,7 +141,7 @@ The test page should contain a list of your attributes:
 Integrating authentication with your own application
 ----------------------------------------------------
 
-The API is documented in [the SP API reference](simplesamlphp-sp-api-reference).
+The API is documented in [the SP API reference](simplesamlphp-sp-api).
 
 For those web resources you want to protect, you must add a few
 lines of PHP code: