Add Hello, World! program in OCaml

hello_world.adb

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+-- hello_world.adb
+with Ada.Text_IO; use Ada.Text_IO;
+
+procedure Hello_World is
+begin
+    Put_Line("Hello, World!");
+end Hello_World;
+

hello_world.cob

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+       IDENTIFICATION DIVISION.
+       PROGRAM-ID. HelloWorld.
+       PROCEDURE DIVISION.
+           DISPLAY 'Hello, World!'.
+           STOP RUN.

hello_world.ml

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+print_endline "Hello, World!"

hello_world.rpg

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+Dcl-S HelloMsg VARCHAR(50) Inz('Hello, World!');
+
+*Display HelloMsg

hello_world.sql

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+BEGIN
+    DBMS_OUTPUT.PUT_LINE('Hello, World!');
+END;