Update the note about origins of the CssSelector component.

The last rewrite is based on the cssselect which is no longer part of lxml, but was extracted as an independent library.

Author: jakzal

src/Symfony/Component/CssSelector/README.md

@@ -36,10 +36,9 @@ names are lower-cased, the following extra pseudo-classes are supported:
 Resources
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-This component is a port of the Python lxml library, which is copyright Infrae
-and distributed under the BSD license.
-
-Current code is a port of https://github.com/SimonSapin/cssselect/releases/tag/v0.7.1
+This component is a port of the Python cssselect library
+[v0.7.1](https://github.com/SimonSapin/cssselect/releases/tag/v0.7.1),
+which is distributed under the BSD license.
 
 You can run the unit tests with the following command: