refactor(script): Comment steps

pacman-zbm-syslinux-regen.sh

@@ -2,6 +2,8 @@
 
 boot_dir='/boot/syslinux'
 boot_dir="${boot_dir%/}"
+
+# Returns e.g. '/dev/sda1'
 boot_fs="$(findmnt --noheadings --target "${boot_dir}" --output 'SOURCE')" || {
     printf -- '%s\n' \
         'Unable to identify boot drive for '"'${boot_dir}'"' boot dir.' \
@@ -15,14 +17,20 @@ if [[ "$(<<<"${boot_fs}" wc -l)" -gt '1' ]]; then
     exit 1
 fi
 
+# Returns e.g. 'sda1'. This is the format used when traversing through lsblk
+# JSON output.
 boot_fs_name="$(basename "${boot_fs}")"
+
+# May return e.g. 'sda' if "${boot_fs}" has a parent.
 boot_disk="$(lsblk --output 'NAME' --json --tree | jq --raw-output '.[][] | select(.children | length > 0) | select(.children[].name=="'"${boot_fs_name}"'") | .name')"
 if [[ ! "${boot_disk}" ]]; then
     # There's no parent drive over "${boot_fs}" meaning "${boot_fs}" itself
     # already is the parent. This is a file system on a drive and not on a
-    # partition.
+    # partition. We stick to the long-form device name, e.g. '/dev/sda1'.
     boot_disk="${boot_fs}"
 else
+    # We found a parent, e.g. 'sda'. In order to work with commands below
+    # we'll prefix it with '/dev/'.
     boot_disk='/dev/'"${boot_disk}"
 fi