Corrects note about use of named blocks (#10521)

Removes incorrect assertion that functions must use `begin`, `process`, and `end` if any named block is used. 

This implies these blocks are required even if they are empty. Assertion is contradicted later in the document when discussing `process`.

reference/7.3/Microsoft.PowerShell.Core/About/about_Functions_Advanced_Methods.md

@@ -61,13 +61,12 @@ Function Test-ScriptCmdlet
 }
 ```
 
-> [!NOTE]
-> Using either a `begin` or `end` block requires that you define all three
-> blocks. When using any block, all PowerShell code must be inside one
-> of the blocks.
-
 PowerShell 7.3 adds a `clean` block process method.
 
+> [!NOTE]
+> Using any of the three named block above, or `dynamicparam` and `clean`,
+> requires that all code in a function must reside in a named block.
+
 ### `begin`
 
 This block is used to provide optional one-time preprocessing for the function.