Mark `alloc` as undefined for `TinyTds::Result`

[andyundso]

From my understanding, you only need to define an alloc function if you want to define a C struct and store values on it. For example, TinyTds::Client defines such an allocate function to wrap its client. On TinyTds::Result, it does not seem we do have a struct and therefore does not need an alloc function.

Closes #515

[aharpervc]

I assume that the warning from https://github.com/rails-sqlserver/tiny_tds/issues/515 is no longer showing with this?

[andyundso]

Exactly. You can compare the output on the Ruby 3.2 job on the current master and this branch, and you see that the warning no longer shows on the very top of the output.

• master: https://app.circleci.com/pipelines/github/andyundso/tiny_tds/1/workflows/39fa47e7-2353-4a83-801a-c0b2d44f06e0/jobs/26/parallel-runs/0/steps/0-115
• feature branch: https://app.circleci.com/pipelines/github/andyundso/tiny_tds/3/workflows/90ab46ac-8cc5-4a2f-8c94-f84053c26b63/jobs/50/parallel-runs/0/steps/0-115

[Michoels]

Looks great! When will this be released?

[taylorthurlow]

Looks great! When will this be released?

This looks like it went out with v2.1.6 in early December.