Create documentation for the Show Symbols option (#99)

* create trellis layout documentation

* update the /config folder under /dashboards

* update Trellis Layout doc with metadata

* fix Trellis Layout page formatting issues

* create the Show Symbol documentation

* update the Show Symbol doc

Author: DebashisBorgohainO2

docs/images/show-symbol-no.png

@@ -1,4 +1,6 @@
 nav:
 
 - Config Overview: index.md
-- Trellis Layout: trellis-layout.md
+- Trellis Layout: trellis-layout.md
+- Show Symbol: show-symbol.md
+

docs/images/show-symbol-yes.png

@@ -2,4 +2,6 @@ The Config tab in OpenObserve dashboards allows users to customize the behavior,
 
 Learn more: 
 
-- [Trellis Layout](../config/trellis-layout/)
+- [Trellis Layout](../config/trellis-layout/)
+- [Show Symbol](../config/show-symbol/)
+

docs/user-guide/dashboards/config/.pages

@@ -0,0 +1,46 @@
+---
+title: Show Symbol Option in OpenObserve Dashboards
+description: Learn how to configure the Show Symbol option in supported chart types to display or hide data point markers in OpenObserve dashboards.
+---
+This guide describes how to use the **Show Symbol** option in OpenObserve dashboards to display or hide data point markers in supported chart types. This setting improves visual clarity when analyzing time-series data by highlighting values along a plotted line or area.
+
+## Supported Chart Types
+The **Show Symbol** setting is available only for the following chart types:
+
+- Line
+- Area
+- Area Stacked
+
+---
+
+## Configure the Show Symbol Option
+To configure the **Show Symbol** option:
+
+1. In the **Panel Editor**, select a supported chart type. 
+2. Expand the **Config** section on the right side of the screen.
+3. Locate the **Show Symbol** dropdown.
+4. From the **Show Symbol** dropdown, select Yes or No:
+
+    - When you select **Yes**, each data point is marked with a small circle for clear identification.
+    ![Show symbol](../../../images/show-symbol-yes.png)
+    - When you select **No**, the chart renders a continuous line or area without individual point markers.
+    ![Do not show symbol](../../../images/show-symbol-no.png)
+
+---
+
+## Default Behavior and Environment Variable
+The default selection of the **Show Symbol** dropdown is determined by the following environment variable:
+
+```bash
+ZO_DASHBOARD_SHOW_SYMBOL_ENABLED=false  # default
+```
+
+- When set to **true**, the **Show Symbol** dropdown defaults to **Yes**.
+- When set to **false**, the **Show Symbol** dropdown defaults to **No**.
+
+> This setting only controls the default state of the **Show Symbol** dropdown. Users can manually change the setting regardless of the environment variable value.
+
+---
+
+## Limitations
+The **Show Symbol** option is supported only in **Line**, **Area**, and **Area Stacked** charts. It is not available for any other chart types in dashboard panels. If a different chart type is selected, the **Show Symbol** option will not appear in the configuration panel.