chore(markdown): Restructuring dev docs

markdown/dev/reference/api/hooks/inserttext/en.md

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+---
+title: insertText
+---
+
+The `insertText` hook is called when text is about to be inserted during rendering.
+
+Methods attached to the `insertText` hook will receive 2 parameters:
+
+ - `locale` : The language code of the language requested by the user (defaults to `en`)
+ - `text`: The text to be inserted
+
+Unlike most hooks that receive an object that you can make changes to, 
+for this hook you need to return a string. 
+
+This hook is typically used for translation, as is the case
+in [our i18n plugin](/reference/plugins/i18n/).
+
+## Understanding the insertText hook
+
+When we say that *this hook is called when text is about to be inserted*, that is a simplified view.
+In reality, this hook is called:
+
+ - For every value set on data-text
+ - For the combined result of these values, joined together with spaces
+
+Let's use an example to clarify things:
+
+```js
+points.example
+  .attr('data-text', "seamAllowance")
+  .attr('data-text', ": 1cm")
+```
+
+For the example point above, the `insertText` hook will end up being called 3 times:
+
+ - First it will pass `seamAllowance` to the plugin
+ - Then it will pass `: 1cm` to the plugin
+ - Finally it will pass `seamAllowance : 1cm` to the plugin
+
+Having the `insertText` hook only run once with `Seam allowance: 1cm` would be problematic because
+the seam allowance may differ, or perhaps we're using imperial units, and so on.
+
+Instead, you can (and should) divide your text into chunks that need translating, and chunks that do not.
+
+This is also why we're not inserting **Seam allowance** but rather **seamAllowance**; 
+It is merely a key to indicate what translation we want to replace this text with.
+