The link of emacsql should be updated in borg.org

[Eason0210]

@tarsius

The link of emacsql should update to magit/emacsql in the borg/docs/borg.org.

borg/docs/borg.org

Line 249 in 581e117

git submodule add --name emacsql git@github.com:skeeto/emacsql.git lib/emacsql

[tarsius]

Thanks for the report!