[TASK] Add labels in Fluid introduction (#1976)

Add labels for cross-referencing

Co-authored-by: Lina Wolf <48202465+linawolf@users.noreply.github.com>

Documentation/ApiOverview/Fluid/Introduction.rst

@@ -72,6 +72,8 @@ Conditions:
 
 .. index:: Fluid; Directory structure
 
+.. _fluid-directory-structure:
+
 Directory structure
 ===================
 
@@ -114,12 +116,15 @@ In Fluid, the location of these paths is defined with
 
 TYPO3 provides the possibility to set the paths using TypoScript.
 
+.. _fluid-templates:
 
 :file:`Templates`
 -----------------
 
 The template contains the main Fluid template.
 
+.. _fluid-layouts:
+
 :file:`Layouts`
 ---------------
 
@@ -141,7 +146,7 @@ Templates can be used with or without a Layout.
 For example, the layout may like this
 
 .. code-block:: html
-   :caption: my_extension:/Resources/Private/Layouts/Default.html
+   :caption: EXT:my_extension/Resources/Private/Layouts/Default.html
 
    <div class="header">
       <f:render section="Header" />
@@ -157,7 +162,7 @@ sections you use is up to you.
 The template should include the sections which are to be rendered.
 
 .. code-block:: html
-   :caption: my_extension:/Resources/Private/Layouts/Default.html
+   :caption:  EXT:my_extension/Resources/Private/Layouts/Default.html
 
    <f:layout name="Default" />
 
@@ -169,6 +174,9 @@ The template should include the sections which are to be rendered.
       <!-- add main content here ! -->
    </f:section>
 
+
+.. _fluid-partials:
+
 :file:`Partials`
 ----------------