DOC: convert library(si) documentation to DocLog format

src/lib/si.pl

@@ -1,28 +1,36 @@
-/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-   Safe type tests
-   ===============
+/** Safe type tests.
 
-   "si" stands for "sufficiently instantiated".
+   "si" stands for "sufficiently instantiated". It can also be read as
+   "safe inference", so possibly also other predicates are candidates
+   for this library.
 
-   These predicates:
+   A safe type test:
 
-    - throw instantiation errors if the argument is
+    - throws an *instantiation error* if the argument is
       not sufficiently instantiated to make a sound decision
-    - succeed if the argument is of the specified type
-    - fail otherwise.
+    - *succeeds* if the argument is of the specified type
+    - *fails* otherwise.
 
-   For instance, atom_si(A) yields an *instantiation error* if A is a
+   For instance, `atom_si(A)` yields an *instantiation error* if `A` is a
    variable. This is logically sound, since in that case the argument
    is not sufficiently instantiated to make any decision.
 
-   The definitions are taken from:
+   The definitions are taken from [Safer type tests in Prolog](https://stackoverflow.com/questions/27306453/safer-type-tests-in-prolog).
 
-       https://stackoverflow.com/questions/27306453/safer-type-tests-in-prolog
+   Examples:
 
-   "si" can also be read as "safe inference", so possibly also other
-   predicates are candidates for this library.
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
+```
+?- chars_si(Cs).
+   error(instantiation_error,list_si/1).
+?- chars_si([h|Cs]).
+   error(instantiation_error,list_si/1).
+?- chars_si("hello").
+   true.
+?- chars_si(hello).
+   false.
+```
+*/
 
 :- module(si, [atom_si/1,
                integer_si/1,