How to escape underscores when matching against macros?

It appears to me that the underscore syntax for specifying types and slurping arguments is in conflict when matching against macro calls. Consider the following MWE:

```julia
julia> using MacroTools

julia> ex = :(@show f(1))
:(#= REPL[185]:1 =# @show f(1))

julia> MacroTools.@capture(ex, @show args__)
true

julia> args
1-element Vector{Any}:
:(f(1))

julia> ex = :(@code_warntype f(1))
:(#= REPL[183]:1 =# @code_warntype f(1))

julia> MacroTools.@capture(ex, @code_warntype args__)
false
```

Indeed, if you look at the `@macroexpand` output then the `_` in `code_warntype` triggers a `MacroTools.TypeBind`:
```julia
julia> @macroexpand MacroTools.@capture(ex, @code_warntype args__)
quote
#= /home/florian/.julia/packages/MacroTools/qijNY/src/match/macro.jl:66 =#
var"@code" = MacroTools.nothing
args = MacroTools.nothing
#= /home/florian/.julia/packages/MacroTools/qijNY/src/match/macro.jl:67 =#
var"#599#env" = MacroTools.trymatch(Core._expr(:macrocall, MacroTools.TypeBind(Symbol("@code"), Set{Any}([:warntype])), $(QuoteNode(:(#= REPL[191]:1 =#))), :args__), ex)
#= /home/florian/.julia/packages/MacroTools/qijNY/src/match/macro.jl:68 =#
if var"#599#env" === MacroTools.nothing
#= /home/florian/.julia/packages/MacroTools/qijNY/src/match/macro.jl:69 =#
false
else
#= /home/florian/.julia/packages/MacroTools/qijNY/src/match/macro.jl:71 =#
var"@code" = MacroTools.get(var"#599#env", Symbol("@code"), MacroTools.nothing)
args = MacroTools.get(var"#599#env", :args, MacroTools.nothing)
#= /home/florian/.julia/packages/MacroTools/qijNY/src/match/macro.jl:72 =#
true
end
end
```

---

I went through the docs again and realized that there isn't a single example where one matches against a macro. I have been doing this for a while now but only encountered the underscore problem today. Is this kind of matching even supposed to work?

---

This appears on `MacroTools@v0.5.10`.

```julia
julia> versioninfo()
Julia Version 1.9.0-rc1
Commit 3b2e0d8fbc1 (2023-03-07 07:51 UTC)
Platform Info:
OS: Linux (x86_64-linux-gnu)
CPU: 8 × 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz
WORD_SIZE: 64
LIBM: libopenlibm
LLVM: libLLVM-14.0.6 (ORCJIT, tigerlake)
Threads: 1 on 8 virtual cores
Environment:
LD_PRELOAD = /usr/lib64/libstdc++.so.6
```