minor #19403 [Doctrine] Mapping types link (chadyred)

This PR was submitted for the 7.1 branch but it was merged into the 5.4 branch instead.

Discussion
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[Doctrine] Mapping types link

Hello,

I target the anchor of the full list of mapping types instead of the whole chapter in the Doctrine documentation as the topic is about a piece of the doc and not the whole subject

Commits
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1d14659 [Doctrine] Mapping types link

Author: javiereguiluz

doctrine.rst

@@ -889,7 +889,7 @@ Learn more
 
 .. _`Doctrine`: https://www.doctrine-project.org/
 .. _`RFC 3986`: https://www.ietf.org/rfc/rfc3986.txt
-.. _`Doctrine's Mapping Types documentation`: https://www.doctrine-project.org/projects/doctrine-orm/en/current/reference/basic-mapping.html
+.. _`Doctrine's Mapping Types documentation`: https://www.doctrine-project.org/projects/doctrine-orm/en/current/reference/basic-mapping.html#reference-mapping-types
 .. _`Query Builder`: https://www.doctrine-project.org/projects/doctrine-orm/en/current/reference/query-builder.html
 .. _`Doctrine Query Language`: https://www.doctrine-project.org/projects/doctrine-orm/en/current/reference/dql-doctrine-query-language.html
 .. _`Reserved SQL keywords documentation`: https://www.doctrine-project.org/projects/doctrine-orm/en/current/reference/basic-mapping.html#quoting-reserved-words