Warning appears in terminal for macro expression using $

[nathanrboyer]

The warning below appears in the terminal when $ is used to the left of = in a macro expression such as in this
Example Notebook.

┌ Warning: unknown use of `=`. Assignee is unrecognised.
│   ex = :($(Expr(:$, :([:first, :second]))))
└ @ ExpressionExplorer C:\Users\nboyer.AIP\.julia\packages\ExpressionExplorer\2Mxnn\src\explore.jl:177

DataFramesMeta.jl requires this in some cases:

Arguments wrapped entirely in $ or $() are passed directly to the underlying DataFrames.jl functions.
Because of this, in addition to the single-column selectors listed above, multi-argument selectors are allowed.
These include, but are not limited to

Vectors of Symbols, $[:x, :y], strings, $["x", "y"], or integers $[1, 2]
Regular expressions, $(r"^a")
Filtering column selectors, such as $(Not(:x)) and $(Between(:a, :z))

(I'm not figuring out video software just to report a terminal message.)