refinement: add some comment

ts.nu

@@ -7,14 +7,17 @@ def list-tests-in-file [file: path] {
  open --raw $file
  | to text
  | lines
- | do {|lines|
- ($lines | skip 1)
- | zip $lines
- | zip ($lines | skip 2)
+ | do {|x|
+ ($x | skip 1) # target line
+ | zip $x # previous line of target line
+ | zip ($x | skip 2) # next line of target line
  } $in
- | each {|groups| $groups | flatten}
- | filter {|group| $group.1 =~ "=+$" and $group.2 =~ "=+$"}
- | each {|group| $group.0}
+ | each {|group| $group | flatten}
+ | filter {|g|
+ # check for test title surroundings on previous and next line
+ $g.1 =~ "=+$" and $g.2 =~ "=+$"
+ }
+ | each {|g| $g.0}
 }
 
 def list-tests-in-dir [dir: path] {