perf: make pre-commit hooks pass file extensions

- shell-lint: faster evaluation of shell scripts, hook 40% faster;
- *-lint: unify method to find the "find" utility; and
- pre-commit: pass file extensions to lint tools.

scripts/best-program.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+## SPDX-FileCopyrightText: 2024 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+# shellcheck disable=SC2086
+set -eu
+
+command -v git >/dev/null || { echo "Missing program: git" >&2; exit 1; }
+cd "$(git rev-parse --show-toplevel)" || exit 1
+
+for tool in "${@}"; do
+  if ./scripts/requires-program.sh "${tool}" >/dev/null 2>&1; then
+    echo "${tool}"
+    break
+  fi
+done