minor symfony#51713 [Component][AssertMapper] add type hint of an argument in asset mappe… (Sarah-eit)

This PR was submitted for the 7.0 branch but it was merged into the 6.4 branch instead.

Discussion
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[Component][AssertMapper] add type hint of an argument in asset mappe…

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Add type hint of an argument in asset mapper command

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Commits
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9aa9174 [Component][AssertMapper] add type hint of an argument in asset mapper command

Author: nicolas-grekas

src/Symfony/Component/AssetMapper/Command/DebugAssetMapperCommand.php

@@ -96,7 +96,7 @@ private function relativizePath(string $path): string
         return str_replace($this->projectDir.'/', '', $path);
     }
 
-    private function shortenPath($path): string
+    private function shortenPath(string $path): string
     {
         $limit = 50;