Rename clang link from clang-X.Y to clang-X

[sylvestre.ledru]

Summary

As we are only doing X.0.Z releases (not using the minor version), there is no need to keep -X.Y in the version.
So, instead, I propose the following:
Instead of having clang-7.0 in bin/, we will have clang-7

Since also matches was gcc is doing.

[dim]

CMakeLists.txt

422

Please update the descriptions too, e.g. "in the form XX". Though upon reading it more closely, where "into the executable" is the version number placed? Isn't this meant as "into the clang executable name"?

I would propose:
"Major version number that will be appended to the clang executable name"

[dim]

LGTM.

[sylvestre.ledru]

Add to the release notes