Change env variable snippet to match consistency

Co-authored-by: Rick Ratzel <[email protected]>

Author: MathisHammel

docs/cugraph-docs/source/installation/source_build.md

@@ -191,8 +191,9 @@ Next the env_vars.sh file needs to be edited
 vi ./etc/conda/activate.d/env_vars.sh
 
 #!/bin/bash
-export PATH=/usr/local/cuda-13.0/bin:$PATH # or cuda-12.9 depending on the version you're using
-export LD_LIBRARY_PATH=/usr/local/cuda-13.0/lib64:$LD_LIBRARY_PATH # or cuda-12.9
+# for CUDA 13.x
+export PATH=/usr/local/cuda-13.0/bin:$PATH
+export LD_LIBRARY_PATH=/usr/local/cuda-13.0/lib64:$LD_LIBRARY_PATH
 ```
 
 ```