Update Razor to 6.0.0-alpha.1.20418.9.

[NTaylorMullen]

• Contains the fix for Component renames not working as expected: https://github.com/dotnet/aspnetcore/issues/25018

[codecov]

Codecov Report

Merging #4000 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #4000   +/-   ##
=======================================
  Coverage   85.96%   85.96%           
=======================================
  Files          60       60           
  Lines        1852     1852           
  Branches      214      214           
=======================================
  Hits         1592     1592           
  Misses        200      200           
  Partials       60       60           

Flag	Coverage Δ
#integration	100.00% <ø> (ø)
#unit	85.96% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 56cbae6...3030c72. Read the comment docs.

[filipw]

that move 5 -> 6 was pretty quick 😀

[JoeRobich]

Passing CI - https://travis-ci.org/github/OmniSharp/omnisharp-vscode/builds/719182003