Lua doc (#1552)

docs/lua/classes/input_string.md

@@ -0,0 +1,29 @@
+# Class: input_string
+
+## Inherit from 1 class: base_text_element
+
+Class for representing an input field for editing a string value within the GUI.
+
+## Functions (2)
+
+### `get_value()`
+
+- **Returns:**
+  - `string`: Get the value currently written inside the input field.
+
+**Exemple Usage:**
+```lua
+string = input_string:get_value()
+```
+
+### `set_value(val)`
+
+- **Parameters:**
+  - `val` (string): Set the value currently written inside the input field.
+
+**Exemple Usage:**
+```lua
+input_string:set_value(val)
+```
+
+