Fix some typos

CONTRIBUTING.md

@@ -18,7 +18,7 @@ For submodules, changes need to be made against the repository corresponding the
 submodule, and not the main `rust-lang/rust` repository.
 
 For subtrees, prefer sending a PR against the subtree's repository if it does
-not need to be made against the main `rust-lang/rust` repostory (e.g. a
+not need to be made against the main `rust-lang/rust` repository (e.g. a
 rustc-dev-guide change that does not accompany a compiler change).
 
 ## About the [rustc-dev-guide]

library/std/src/sys/pal/uefi/process.rs

@@ -757,7 +757,7 @@ mod uefi_command_internal {
 }
 
 /// Create a map of environment variable changes. Allows efficient setting and rolling back of
-/// enviroment variable changes.
+/// environment variable changes.
 ///
 /// Entry: (Old Value, New Value)
 fn env_changes(env: &CommandEnv) -> Option<BTreeMap<EnvKey, (Option<OsString>, Option<OsString>)>> {

src/doc/rustc/src/platform-support/riscv64gc-unknown-linux-gnu.md

@@ -65,7 +65,7 @@ section below.
 
 A RISC-V toolchain can be obtained for Windows/Mac/Linux from the
 [`riscv-gnu-toolchain`](https://github.com/riscv-collab/riscv-gnu-toolchain)
-repostory. Binaries are available via
+repository. Binaries are available via
 [embecosm](https://www.embecosm.com/resources/tool-chain-downloads/#riscv-linux),
 and may also be available from your OS's package manager.