Another small grammar fix for process.rs

Author: sourcefrog

src/libstd/process.rs

@@ -300,7 +300,7 @@ impl Command {
  /// Executes a command as a child process, waiting for it to finish and
  /// collecting its exit status.
  ///
- /// By default, stdin, stdout and stderr are inherited by the parent.
+ /// By default, stdin, stdout and stderr are inherited from the parent.
  ///
  /// # Examples
  ///