Add interrupt.pyx to the reference manual

Also add back pselect.pyx, which was removed by mistake in 4d2df6a.

src/c_lib/src/interrupt.c

@@ -132,8 +132,8 @@ void sage_interrupt_handler(int sig)
     else
     {
         /* Set the Python interrupt indicator, which will cause the
-         * Python-level interrupt handler in sage/ext/c_lib.pyx to be
-         * called. */
+         * Python-level interrupt handler in sage/ext/interrupt.pyx to
+         * be called. */
         PyErr_SetInterrupt();
     }
 

src/doc/en/reference/libs/index.rst

@@ -67,6 +67,9 @@ to be aware of the modules described in this chapter.
 
    sage/gsl/gsl_array
 
+   sage/ext/interrupt
+   sage/ext/pselect
+
 .. Cannot be imported independently of mpmath: sage/libs/mpmath/ext_main sage/libs/mpmath/ext_impl sage/libs/mpmath/ext_libmp
 
 .. Modules depending on optional packages: sage/libs/coxeter3/coxeter sage/libs/coxeter3/coxeter_group sage/libs/fes

src/sage/ext/interrupt.pyx

@@ -1,5 +1,5 @@
 r"""
-Cython interface to the interrupt handling code.
+Cython interface to the interrupt handling code
 
 See ``src/sage/tests/interrupt.pyx`` for extensive tests.