Move exit status section after errors section

It is more natural to read the errors section first, and then the exit
status section which usually refers to the just-described errors.

See also commit c97e4e3.

yash-builtin/src/pwd.rs

@@ -46,17 +46,17 @@
 //!
 //! None.
 //!
-//! # Exit Status
-//!
-//! Zero if the path was successfully printed; non-zero otherwise.
-//!
 //! # Errors
 //!
 //! This built-in may fail for various reasons. For example:
 //! - The working directory has been removed from the file system.
 //! - You do not have permission to access the ancestor directories of the working directory.
 //! - The standard output is not writable.
 //!
+//! # Exit Status
+//!
+//! Zero if the path was successfully printed; non-zero otherwise.
+//!
 //! # Portability
 //!
 //! The `-L` and `-P` options are defined in POSIX.

yash-builtin/src/typeset.rs

@@ -225,10 +225,6 @@
 //! may fail if functions are read-only since the read-only functions cannot be
 //! redefined.
 //!
-//! # Exit status
-//!
-//! Zero unless an error occurs.
-//!
 //! # Errors
 //!
 //! The read-only attribute cannot be removed from a variable or function. If a
@@ -239,6 +235,10 @@
 //! When printing variables or functions, it is an error if an operand names a
 //! non-existing variable or function.
 //!
+//! # Exit status
+//!
+//! Zero unless an error occurs.
+//!
 //! # Portability
 //!
 //! The typeset built-in is not specified by POSIX and many shells implement it