Update name of Convert to MeshInstance2D button in MeshInstance2D doc
Update name of Convert to MeshInstance2D button in MeshInstance2D doc

(cherry picked from commit 857e5a3bb065e8efdbb137796c3ba4946eaab99b)

ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot