doc: add STOP keyword

docs/do.md

@@ -16,7 +16,7 @@ LOOP: REM This loop repeats forever.
 
 This form **loops forever**. It's better to use this form instead of using **STEP** 0 in a **FOR** loop, or a **WHILE** 1 condition loop. The generated code is more efficient.
 
-###Looping UNTIL
+### Looping UNTIL
 
 ```
 DO
@@ -38,7 +38,7 @@ LOOP
 
 In this case, the condition is checked first, and the program won't enter to the inner _sentences_ if the condition is not satisfied at first.
 
-####Example using UNTIL
+#### Example using UNTIL
 Example: _Loop until the user press a Key_
 
 ```
@@ -47,7 +47,7 @@ DO LOOP UNTIL INKEY$ <> ""
 ```
 
 
-###Looping WHILE
+### Looping WHILE
 
 ```
 DO
@@ -70,7 +70,7 @@ LOOP
 
 In this case, the condition is checked first, and the program won't enter to the inner _sentences_ if the condition is not satisfied at first.
 
-####Example using WHILE
+#### Example using WHILE
 Example: _Loop while there is no key pressed_
 
 ```
@@ -79,11 +79,11 @@ DO LOOP WHILE INKEY$ = ""
 ```
 
 
-##Remarks
+## Remarks
 * This statement does not exist in Sinclair Basic.
 * **WHILE** can also be used with [WHILE ... END WHILE](while.md) loops.
 
-##See Also
+## See Also
 * [IF ... END IF](if.md)
 * [WHILE ... END WHILE](while.md)
 * [FOR ... NEXT](for.md)

docs/end.md

@@ -15,5 +15,8 @@ PRINT "HELLO WORLD"
 END 32: REM The value 32 will be returned to the OS
 ```
 
-End is also a keyword used to close [scopes](scope.md) in [FUNCTION](function.md) and [SUB](sub.md)
+`END` is also a keyword used to close [scopes](scope.md) in [FUNCTION](function.md) and [SUB](sub.md)
 and compound sentences in [IF](if.md), [WHILE](while.md).
+
+## See Also
+ * [STOP](stop.md)

docs/stop.md

@@ -0,0 +1,18 @@
+# STOP
+
+
+## Syntax
+```
+STOP
+```
+
+Terminates execution and returns to the Operating System (i.e. to the Sinclair
+BASIC interpreter).
+
+```basic
+PRINT "HELLO WORLD"
+STOP
+```
+
+## See Also
+ * [END](end.md)