Update docs/apps/singularity.md

code review from Oscar

Co-authored-by: Oscar Esteban <[email protected]>

Author: mckenziephagen

docs/apps/singularity.md

@@ -4,7 +4,8 @@
     To illustrate the process, we will show the execution of *fMRIPrep*, but these guidelines extend to any other end-user *NiPrep*.
 
 !!! warning "Apptainer"
-    In 2021, Singularity was migrated and became Apptainer. Despite this, all below commands that contain `singularity` will execute Apptainer, and can be replaced with the `apptainer` command with no change in function. 
+    In 2021, [*Singularity* was rebranded as *Apptainer* when the project was transferred to the Linux Foundation](https://apptainer.org/news/community-announcement-20211130/).
+    As noted in the community announcement, all the commands below that contain `singularity` as the command line executable will execute *Apptainer* and can be replaced with the `apptainer` command with no change in function. 
 
 ## Preparing a Singularity image