Mention rustup upgrade in install instructions

[sophiebits]

I had installed rustup a while ago but sat down today to try Rust again; it wasn't obvious to me how to get the latest Rust.

[chriskrycho]

This is a nice suggested improvement – with just one very small tweak, please!

[meven]

I don't know this "update" subcommand shouldn't is be "update" ?

rustup -h
rustup 1.15.0 (f0a3d9a84 2018-11-27)
The Rust toolchain installer

USAGE:
rustup [FLAGS]

FLAGS:
-v, --verbose Enable verbose output
-h, --help Prints help information
-V, --version Prints version information

SUBCOMMANDS:
show Show the active and installed toolchains
update Update Rust toolchains and rustup
default Set the default toolchain
toolchain Modify or query the installed toolchains
target Modify a toolchain's supported targets
component Modify a toolchain's installed components
override Modify directory toolchain overrides
run Run a command with an environment configured for a given toolchain
which Display which binary will be run for a given command
doc Open the documentation for the current toolchain
man View the man page for a given command
self Modify the rustup installation
set Alter rustup settings
completions Generate completion scripts for your shell
help Prints this message or the help of the given subcommand(s)

[chriskrycho]

Oh, great catch! Do you have a few minutes to open a PR fixing that word, @meven? I'll happily review and merge it!

[meven]

PR opened ;)

[sophiebits]

That’s embarrassing! The choice to use “update” in prose was intentional but I meant to write “upgrade” in the command. Thanks for fixing!