Update the ballerina library word

examples/programs-and-modules/programs_and_modules.bal

@@ -1,6 +1,6 @@
 // This import declaration binds the prefix `io` to the `ballerina/io` module. 
 // The prefix by default comes form the last part of the module name.
-// The `ballerina` org name is reserved for the standard library modules.
+// The `ballerina` org name is reserved for the Ballerina library packages.
 import ballerina/io;
 
 // `main` function is the program entry point.