fix wrong linking (#174)

Author: finkandreas

docs/clusters/eiger.md

@@ -29,7 +29,7 @@ Eiger is an Alps cluster that provides compute nodes and file systems designed t
     ### Unimplemented features
 
     !!! under-construction "Jupyter is not yet available"
-        [Jupyter][ref-jupyter] has not yet been configured on `Eiger.Alps`.
+        [Jupyter][ref-jlab] has not yet been configured on `Eiger.Alps`.
 
         **It will be deployed as soon as possible and this documentation will be updated accordingly**
 
@@ -161,7 +161,7 @@ See the Slurm documentation for instructions on how to run jobs on the [AMD CPU
 ### Jupyter and FirecREST
 
 !!! under-construction "FirecREST is not yet available"
-    [Jupyter][ref-jupyter] has not yet been configured on `Eiger.Alps`.
+    [Jupyter][ref-jlab] has not yet been configured on `Eiger.Alps`.
 
     **It will be deployed as soon as possible and this documentation will be updated accordingly**