Clarify documentation in dns_txt_query_exec

[zeroSteiner]

This makes some major changes to the module information for the windows/dns_txt_query_exec module to help clarify how it works for users. I also clarified a couple of key comments in the shellcode to document that the returned struct is a DNS_TXT_DATAA instance and that it's checking the number of strings in that field. I ran into this while debugging the payload to figure out why it wasn't working.

Verification

I recommend reviewing while ignoring whitespace. There were a lot of tabs that were breaking the indentation of the shellcode comments.

• Read through the module description and have a better understanding of what the payload is doing
• Read through the shellcode and understand what it's doing

This PR makes no functional changes, nothing in the shellcode other than comments and whitespace should have changed so it shouldn't be necessary to test it again.

[adfoster-r7]

Release Notes

Adds additional documentation to the windows/dns_txt_query_exec module to help clarify how it works for users