Fix: Add missing method visibility in interface excerpts

PSR-2, that's why.
minor #1061 Fix: Add missing method visibility in interface excerpts (localheinz)

This PR was submitted for the master branch but it was merged into the 1.2 branch instead (closes #1061).

Discussion
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Fix: Add missing method visibility in interface excerpts

PSR-2, that's why.

Commits
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fc9c1b7 Fix: Add missing method visibility in interface excerpts