Brought documentation for sqlite3 module up-to-date. Fixed Issue1625205 which

complained about commit, rollback and close not being documented.

Doc/includes/sqlite3/ctx_manager.py

@@ -0,0 +1,16 @@
+import sqlite3
+
+con = sqlite3.connect(":memory:")
+con.execute("create table person (id integer primary key, firstname varchar unique)")
+
+# Successful, con.commit() is called automatically afterwards
+with con:
+    con.execute("insert into person(firstname) values (?)", ("Joe",))
+
+# con.rollback() is called after the with block finishes with an exception, the
+# exception is still raised and must be catched
+try:
+    with con:
+        con.execute("insert into person(firstname) values (?)", ("Joe",))
+except sqlite3.IntegrityError:
+    print "couldn't add Joe twice"