add the md files from the docs repo to start updating them to v8

docs/widgets/line.md

@@ -0,0 +1,52 @@
+```eval_rst
+.. include:: /header.rst 
+:github_url: |github_link_base|/widgets/line.md
+```
+# Line (lv_line)
+
+## Overview
+The Line object is capable of drawing straight lines between a set of points.
+
+## Parts and Styles
+The Line has only a main part, called `LV_LABEL_PART_MAIN`. It uses all the *line* style properties.
+
+## Usage
+
+### Set points 
+The points has to be stored in an `lv_point_t` array and passed to the object by the `lv_line_set_points(lines, point_array, point_cnt)` function. 
+
+### Auto-size
+It is possible to automatically set the size of the line object according to its points. 
+It can be enable with the `lv_line_set_auto_size(line, true)` function. 
+If enabled then when the points are set the object's width and height will be changed according to the maximal x and y coordinates among the points. The *auto size* is enabled by default.
+
+### Invert y
+By deafult, the *y == 0* point is in the top of the object. It might be conter-intuitive in some cases so the y coordinates can be inverted with `lv_line_set_y_invert(line, true)`. In this case,  *y == 0* will be the bottom of teh obejct. 
+The *y invert* is disabled by default.
+
+## Events
+Only the [Generic events](../overview/event.html#generic-events) are sent by the object type.
+
+Learn more about [Events](/overview/event).
+
+## Keys
+No *Keys* are processed by the object type.
+
+Learn more about [Keys](/overview/indev).
+
+## Example
+
+```eval_rst
+
+.. include:: /lv_examples/src/lv_ex_widgets/lv_ex_line/index.rst
+
+```
+
+## API 
+
+```eval_rst
+
+.. doxygenfile:: lv_line.h
+  :project: lvgl
+        
+```