docs: adjust wordings "composer mode" / "classic mode"

Author: brotkrueml

Documentation/Command/Index.rst

@@ -14,13 +14,13 @@ can call it on the console with:
 
 .. tabs::
 
-   .. group-tab:: Composer-based installation
+   .. group-tab:: Composer mode
 
       .. code-block:: bash
 
          vendor/bin/typo3 formratelimit:cleanupexpiredstorageentries
 
-   .. group-tab:: Legacy installation
+   .. group-tab:: Classic mode
 
       .. code-block:: bash
 

Documentation/Installation/Index.rst

@@ -20,7 +20,7 @@ Composer-based TYPO3 project root, just type:
 
 and the recent stable version will be installed.
 
-In legacy installations, you can also install the extension from the
+In classic mode, you can also install the extension from the
 `TYPO3 Extension Repository (TER)`_.
 
 Then continue with the :ref:`configuration <configuration>`.