chore: improve script docs

Author: Conaclos

scripts/print-changelog.sh

@@ -1,6 +1,8 @@
 #!/bin/sh
 set -eu
 
+# This script is used by our GitHub release workflow (./.github/workflows/release-github.yml)
+
 # Print a changelog section (default: first section).
 
 VERSION=''

scripts/version.sh

@@ -1,6 +1,8 @@
 #!/bin/sh
 set -eu
 
+# This script is run on `npm version` (See ./package.json).
+
 # check presence of 'Unreleased' string
 grep --quiet '^## Unreleased$' CHANGELOG.md