docs: titles added to some important admonitions

docs/users_guide/framework_basics/text_output.md

@@ -66,10 +66,10 @@ The text output will always print the [value of a quantity](../../appendix/gloss
 typically followed by a space and then the symbol of a [unit](../../appendix/glossary.md#unit)
 associated with this quantity.
 
-!!! important
+!!! important "Important: Don't assume a unit"
 
-    Remember that when we deal with a quantity of an "unknown" `auto` type, it is a good practice
-    to always [convert the unit to the expected one](value_conversions.md#value-conversions)
+    Remember that when we deal with a quantity of an "unknown" (e.g. `auto`) type, it is a good
+    practice to always [convert the unit to the expected one](value_conversions.md#value-conversions)
     before passing it to the text output:
 
     ```cpp