minor symfony#57295 [Mime] Tweak an exception to be more descriptive (fabpot)

This PR was merged into the 7.2 branch.

Discussion
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[Mime] Tweak an exception to be more descriptive

| Q             | A
| ------------- | ---
| Branch?       | 7.2
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Issues        | Fix symfony#54162 <!-- prefix each issue number with "Fix #", no need to create an issue if none exists, explain below instead -->
| License       | MIT

Commits
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b5cacc9 [Mime] Tweak an exception to be more descriptive

Author: fabpot

src/Symfony/Component/Mime/Part/DataPart.php

@@ -66,7 +66,7 @@ public function asInline(): static
     public function setContentId(string $cid): static
     {
         if (!str_contains($cid, '@')) {
-            throw new InvalidArgumentException(sprintf('Invalid cid "%s".', $cid));
+            throw new InvalidArgumentException(sprintf('The "%s" CID is invalid as it doesn\'t contain an "@".', $cid));
         }
 
         $this->cid = $cid;