more migration to common docs (#370)

* more migration to common docs

* refactoring js

* removed duplicate docs

* migrating more docs

* more refactoring

* migrated browsers page

* updated summary

docs/blocks/loops/for.md

@@ -1,13 +1,6 @@
-# For
+# @extends
 
-### @parent blocks/language
- 
-Run part of the program the number of times you say.
-
-```block
-for(let i = 0; i <= 4; ++i) {
-}
-```
+## #examples
 
 ### Example: Count to 4
 
@@ -20,8 +13,3 @@ input.onButtonPressed(Button.A, () => {
     }
 })
 ```
-
-### See also
-
-[repeat](/blocks/loops/repeat), [while](/blocks/loops/while), [if](/blocks/logic/if), [show number](/reference/basic/show-number)
-

docs/blocks/loops/repeat.md

@@ -1,12 +0,0 @@
-# Repeat
-
-Run part of the program the number of times you say.
-
-### Block Editor
-
-![](/static/mb/blocks/contents-0.png)
-
-### See also
-
-[for](/blocks/loops/for), [while](/blocks/loops/while), [if](/blocks/logic/if), [show number](/reference/basic/show-number)
-

docs/blocks/loops/while.md

@@ -1,15 +1,6 @@
-# While
+# @extends
 
-Repeat code while a [Boolean](/blocks/logic/boolean) `condition` is true.
-
-```block
-while(true) {
-}
-```
-
-The while loop has a *condition* that evaluates to a [Boolean](/blocks/logic/boolean) value. After the `do` keyword, add the code that you want to run while the `condition` is `true`. The while loop concludes with `end while`.
-
-The condition is tested before any code runs. Which means that if the condition is false, the code inside the loop doesn't execute.
+## #examples
 
 ### Example: diagonal line
 
@@ -24,8 +15,3 @@ input.onButtonPressed(Button.A, () => {
     }
 })
 ```
-
-### See also
-
-[on button pressed](/reference/input/on-button-pressed), [for](/blocks/loops/for), [if](/blocks/logic/if), [forever](/reference/basic/forever)
-