fixing doc roles
fix PHP code block
fix table syntax
fix seealso directive name
minor #3650 Fixing some build errors (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
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Fixing some build errors

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets |

Commits
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62d4a97 fix seealso directive name
62586a4 fix table syntax
72659e2 fix PHP code block
c7f2ee6 fixing doc roles