address comments

doc/src/basics.md

@@ -39,7 +39,7 @@ variable.  This setting supports three values: `enable` and `disable` and `check
 * `enable` will mean that `rustup update` and similar commands will also check-for, and install, any update to Rustup.
 * `check-only` will cause any automatic self update to check and report on any updates, but not to automatically install them.
 
-Whether automatic self-update is enabled or not, you can request that Rustup check for, and update it self to the
+Whether automatic self-update is enabled or not, you can request that Rustup check for, and update itself to the
 latest version of `rustup` without updating any installed toolchains by running `rustup
 self update`:
 
@@ -49,7 +49,8 @@ info: checking for self-updates
 info: downloading self-updates
 ```
 
-**Note**: If auto-self-update is `enable`, `rustup` will automatically update itself at the end of any
+### Disable automatic self-updates with the parameter of the command
+If auto-self-update is `enable`, `rustup` will automatically update itself at the end of any
 toolchain installation as well.  You can prevent this automatic behaviour by
 passing the `--no-self-update` argument when running `rustup update` or
 `rustup toolchain install`.

src/cli/rustup_mode.rs

@@ -1586,6 +1586,9 @@ fn set_profile(cfg: &mut Cfg, m: &ArgMatches<'_>) -> Result<utils::ExitCode> {
 }
 
 fn set_auto_self_update(cfg: &mut Cfg, m: &ArgMatches<'_>) -> Result<utils::ExitCode> {
+    if self_update::NEVER_SELF_UPDATE {
+        writeln!(process().stdout(), "Your rustup is built with the no-self-update feature, so setting auto-self-update will not have any effect.")?;
+    }
     cfg.set_auto_self_update(&m.value_of("auto-self-update-mode").unwrap())?;
     Ok(utils::ExitCode(0))
 }