Coding standards

static MUST be declared after the visibility (PSR-2)
minor #10006 Fixed coding standards (PSR-2) (cmfcmf)

This PR was submitted for the 2.3-dev branch but it was merged into the 2.3 branch instead (closes #10006).

Discussion
----------

Fixed coding standards (PSR-2)

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | ---
| Fixed tickets | ---
| License       | MIT
| Doc PR        | ---

> static MUST be declared after the visibility
-- (PSR-2)

Commits
-------

2fbc833 Coding standards