References to rtx are out-of-date

[medwards1771]

Explain the changes

rtx is now mise ! per this post from the tool's maintainer, "The name was changed to avoid confusion with Nvidia's line of graphics cards. This wasn't a legal issue, but just general confusion."

Suggested changes

update references to rtx with references to mise. (i plan create a PR for this)

Additional context

i also plan to create a follow-up PR to rename the .rtx.toml file in forem to .mise.toml and update any config as needed per the instructions from https://mise.jdx.dev/rtx.html:

mise will continue reading .rtx.toml files for some time but that eventually will be deprecated so please rename them to .mise.toml. mise will not read from RTX_* env vars so those will need to be changed to MISE_*. Anything using a local .rtx or .config/rtx directory will need to be moved to .mise/.config/mise.

[maestromac]

Resolved