chore: fix some typos in comments

Signed-off-by: cuiyourong <cuiyourong@gmail.com>

Author: cuiyourong

src/cli/self_update.rs

@@ -1178,7 +1178,7 @@ pub(crate) fn prepare_update() -> Result<Option<PathBuf>> {
 
     // For windows x86 builds seem slow when used with windows defender.
     // The website defaulted to i686-windows-gnu builds for a long time.
-    // This ensures that we update to a version thats appropriate for users
+    // This ensures that we update to a version that's appropriate for users
     // and also works around if the website messed up the detection.
     // If someone really wants to use another version, they still can enforce
     // that using the environment variable RUSTUP_OVERRIDE_HOST_TRIPLE.

src/config.rs

@@ -906,7 +906,7 @@ impl Cfg {
         // breadcrumb in case of regression: we used to get the cargo path and
         // cargo.exe path separately, not using the binary_file helper. This may
         // matter if calling a binary with some personality that allows .exe and
-        // not .exe to coexist (e.g. wine) - but thats not something we aim to
+        // not .exe to coexist (e.g. wine) - but that's not something we aim to
         // support : the host should always be correct.
         if cargo_path.exists() {
             return Ok(None);