feat(cli): add --watch to astro check command (#6356)

* feat(cli): add `--watch` to `astro check` command

* chore: refactor in a leaner way, logic not changed

* chore: lint

* chore: revert changes in sync command

* chore: tweak server settings

* test: add one test case

* chore: increase timeout

* test: predictable testing

* chore: add changeset

* chore: code suggestions

* code suggestions

* chore: use directly `chokidar`

* chore: tweak code

* fix: open documents first

* chore: disable test

* chore: code suggestions

* chore: code suggestions

* Apply suggestions from code review

Co-authored-by: Erika <3019731+Princesseuh@users.noreply.github.com>

* code suggestions

* chore: rebase

---------

Co-authored-by: Erika <3019731+Princesseuh@users.noreply.github.com>

.changeset/six-moons-taste.md

@@ -0,0 +1,5 @@
+---
+'astro': minor
+---
+
+Added a new `--watch` flag to the command `astro check`

packages/astro/package.json

@@ -113,6 +113,7 @@
     "@types/yargs-parser": "^21.0.0",
     "acorn": "^8.8.1",
     "boxen": "^6.2.1",
+    "chokidar": "^3.5.3",
     "ci-info": "^3.3.1",
     "common-ancestor-path": "^1.0.1",
     "cookie": "^0.5.0",