Rollup merge of #44141 - nrc:rls-preview-beta, r=alexcrichton
Rollup merge of #44141 - nrc:rls-preview-beta, r=alexcrichton

Rename the rls component to rls-preview on beta/stable

Background is that we will have automatic renaming with the next rustup release. We'll then rename rls to rls-preview. In the meantime, this ensures beta/stable users will always have rls-preview.

r? @alexcrichton

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,GBGamer/rust,aidancully/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,GBGamer/rust,graydon/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust