fix(tech debt): allow multiple paths for adaptation notes (#21241)

Reported on [Zulip](https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Technical.20Debt.20Counters/near/496481255).

scripts/technical-debt-metrics.sh

@@ -73,11 +73,14 @@ computeDiff () {
 # The script uses the fact that a line represents a technical debt if and only if the text before
 # the first `|` is a number.  This is then used for comparison and formatting.
 tdc () {
+# We perform word-splitting "by hand" in the "middle" entries.
+# See also the comment on the `read` line in the for-loop that follows the definition of this array.
 titlesPathsAndRegexes=(
   "porting notes"                  "*"      "Porting note"
   "backwards compatibility flags"  "*"      "set_option.*backward"
   "skipAssignedInstances flags"    "*"      "set_option tactic.skipAssignedInstances"
-  "adaptation notes"               ":^Mathlib/Tactic/AdaptationNote.lean" "^[· ]*#adaptation_note"
+  "adaptation notes"               ":^Mathlib/Tactic/AdaptationNote.lean :^Mathlib/Tactic/Linter"
+                                            "^[· ]*#adaptation_note"
   "disabled simpNF lints"          "*"      "nolint simpNF"
   "erw"                            "*"      "erw \["
   "maxHeartBeats modifications"    ":^MathlibTest" "^ *set_option .*maxHeartbeats"
@@ -87,13 +90,15 @@ for i in ${!titlesPathsAndRegexes[@]}; do
   # loop on every 3rd entry and name that entry and the following two
   if (( i % 3 == 0 )); then
     title="${titlesPathsAndRegexes[$i]}"
-    pathspec="${titlesPathsAndRegexes[$(( i + 1 ))]}"
+    # Here we perform word-splitting: `pathspec` is an array whose entries are the "words" in
+    # the string `"${titlesPathsAndRegexes[$(( i + 1 ))]}"`.
+    read -r -a pathspec <<< "${titlesPathsAndRegexes[$(( i + 1 ))]}"
     regex="${titlesPathsAndRegexes[$(( i + 2 ))]}"
     if [ "${title}" == "porting notes" ]
     then fl="-i"  # just for porting notes we ignore the case in the regex
     else fl="--"
     fi
-    printf '%s|%s\n' "$(git grep "${fl}" "${regex}" -- ":^scripts" "${pathspec}" | wc -l)" "${title}"
+    printf '%s|%s\n' "$(git grep "${fl}" "${regex}" -- ":^scripts" "${pathspec[@]}" | wc -l)" "${title}"
   fi
 done