Links to "Edit in Github" page broken in doc

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This may be solved by setting the EditURL of the @meta block:

https://juliadocs.github.io/Documenter.jl/stable/man/syntax/#@meta-block

test in b0253fb

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The problem is with .md files. The pages generated from .jl files in the doc folder seem OK.

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This seems to be sorted for now. Main page of the doc file, from the readme, links to the main github repo.
The only issue is that the meta-block is visible at the bottom of the README file.
It should be possible to add this block dynamically when the doc is generated as part of the make.jl script.
--> #132