NO-JIRA: docs: update outdated internal docs after the buildchain refactoring (#1028)

Author: jiridanek

jupyter/utils/README.md

@@ -1,5 +1,4 @@
 # Shared files for all JupyterLab workbenches we have
 
 These files were initially duplicated into many `jupyter/` subdirectories.
-In general, they are incorporated into every JupyterLab workbench,
-but sometimes that's through building `FROM` base `datascience` image and not `COPY`ed directly.
+In general, they are incorporated into every JupyterLab workbench.

jupyter/utils/addons/apply.sh

@@ -2,7 +2,6 @@
 
 # See https://github.com/jupyterlab/jupyterlab/issues/5463
 # This is a hack to apply partial HTML code to JupyterLab's `index.html` file
-# Look for the other duplicates in case a change is needed to this file
 
 script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"