fix: exclude .gitattributes from exports in Core and Ses (#2072)

* docs: exclude .gitattributes from exports in Core and Ses

* docs: add export-ignore for .gitattributes and fix trailing newline

* Add missing entries

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Co-authored-by: AAMIR AKRAM <91816147+Aamir-Akram@users.noreply.github.com>
Co-authored-by: Jérémy Derussé <jeremy@derusse.com>

Author: Root-Aamir

.gitattributes

@@ -3,3 +3,4 @@
 /.gitignore export-ignore
 /Makefile export-ignore
 /phpunit.xml.dist export-ignore
+/.gitattributes export-ignore