Fix singularity docs (#2493) [ci skip]

Signed-off-by: JoseEspinosa <kadomu@gmail.com>

docs/singularity.rst

@@ -151,8 +151,8 @@ or the ``singularity.cacheDir`` setting in the Nextflow config file.
 
 As of version ``21.09.0-edge``, when looking for a Singularity image file, Nextflow before checks the *library* directory,
 if the image file is not found, the *cache* directory is used as usual. The library directory can be defined either using
-the ``NXF_SINGULARITY_LIBRARYDIR`` environment variable or the ``singularity.libraryDir`` configuration setting (the latter
-overrides th
+the ``NXF_SINGULARITY_LIBRARYDIR`` environment variable or the ``singularity.libraryDir`` configuration setting (the
+latter overrides the former).
 
 .. warning:: When using a computing cluster the Singularity cache directory must be a shared folder accessible
   to all computing nodes.