[IMP] developer: explain the new <asset> tag added as a fix

Also removes outdated things in the `<template>` tag documentation and
reviews it a bit.

See https://github.com/odoo/odoo/pull/104836

task-2963840

closes odoo/documentation#15051

X-original-commit: 7ee3426484
Related: odoo/odoo#233402
Related: odoo/enterprise#98250
Related: odoo/design-themes#1174
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

content/developer/reference/frontend/assets.rst

@@ -362,3 +362,15 @@ manifest counterparts.
 `sequence` (default= `16`)
     Loading order of the asset records (ascending). A sequence lower than 16 means
     that the asset will be processed *before* the ones declared in the manifest.
+
+.. seealso::
+
+    Note that the ``ir.asset`` use case is mainly for website-related
+    applications, as it allows for conditional assets (for example, when a style
+    option is enabled).
+
+    In such cases, the ``<asset id="...">`` syntax should be preferred over the
+    ``<record id="..." model="ir.asset">`` syntax when defining the record in
+    XML.
+
+    See :ref:`reference/data/asset`, especially about the ``active`` value.