update query web param --as-table from Table to List (#11531)

# Description

This is a small change that updates the `--as-table`/`-t` parameter to
`SyntaxShape::List` instead of `SyntaxShape::Table`. It was always
supposed to be a list of headers. Not sure where Table came from.

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crates/nu_plugin_query/src/nu/mod.rs

@@ -32,7 +32,7 @@ impl Plugin for Query {
             )
             .named(
                 "as-table",
-                SyntaxShape::Table(vec![]),
+                SyntaxShape::List(Box::new(SyntaxShape::String)),
                 "find table based on column header list",
                 Some('t'),
             )