chore(tools): don't fail npm run new when VS Code CLI is missing - #3116

Closes #2781

npm run new <rule name> <author name> writes the rule, test and docs files and then opens them with the VS Code CLI. When code is not on PATH — the contributor uses another editor, or VS Code is installed without the shell command — the first execSync throws:

/bin/sh: code: command not found
Error: Command failed: code "path/to/generated/file"
    at Object.execSync (node:child_process:954:15)
    at tools/new-rule.js:143:6

All three files are generated successfully at that point, but:

• the remaining two files are never opened, because the first execSync throws;
• the script exits with code 1 and a Node stack trace, so it looks like the generation itself failed;
• the paths of the generated files are never printed, so it is not obvious what was created.

This is the first command a new contributor runs from the developer guide, so it is worth failing softly.

Changes

• print the paths of the generated files;
• wrap the editor launch in try/catch and ignore the failure — the files are already on disk, there is nothing to recover from.

Verification

Without code on PATH:

$ npm run new some-rule Someone
Created:
  lib/rules/some-rule.ts
  tests/lib/rules/some-rule.test.ts
  docs/rules/some-rule.md
$ echo $?
0

With code on PATH the three files are still opened as before.

No changeset: tools/ is not part of the published package ("files": ["dist"]), same as #3049