Fixed an error in merge-three-line-headers
Fixed an error in merge-three-line-headers

I forgot to rename the contents variable to c in the right hand side of the
rule. This has been corrected

DrItanium/electron-platform,DrItanium/electron-platform,DrItanium/electron,DrItanium/neutron,DrItanium/electron,DrItanium/AdventureEngine,DrItanium/electron-platform,DrItanium/electron,DrItanium/AdventureEngine