fix: avoid echo usage

Echo can interpret operand as an option and checking every variable to
be echoed is troublesome while with printf, if the format specifier is
present before the operand, printing as string can be enforced.

scripts/best-program.sh

@@ -7,7 +7,8 @@
 # shellcheck disable=SC2086
 set -eu
 
-command -v git >/dev/null || { echo "Missing program: git" >&2; exit 1; }
+command -v git >/dev/null ||
+  { printf '%s\n' "Missing program: git" >&2; exit 1; }
 repo_toplevel="$(git rev-parse --show-toplevel)"
 test -d "${repo_toplevel}" || exit 1
 cd "${repo_toplevel}"
@@ -15,7 +16,7 @@ unset repo_toplevel
 
 for tool in "${@}"; do
   if ./scripts/requires-program.sh "${tool}" >/dev/null 2>&1; then
-    echo "${tool}"
+    printf '%s\n' "${tool}"
     break
   fi
 done