triagebot: temporarily disable auto compiler backport nominations

No prejudice against re-enabling them if the nominations include a bit
more context on _why_ it's automatically nominated and _which_
regression(s) are being addressed. Or as proposed, it could also simply
become a reminder-to-nominate _comment_.

Author: jieyouxu

triagebot.toml

@@ -50,21 +50,6 @@ remove_labels = ["S-waiting-on-author"]
 # Those labels are added when PR author requests a review from an assignee
 add_labels = ["S-waiting-on-review"]
 
-# [backport.*] sections autonominate pull requests for a backport
-# see: https://forge.rust-lang.org/triagebot/backport.html
-
-[backport.t-compiler-beta-backport]
-# The pull request MUST have one of these labels
-required-pr-labels = ["T-compiler"]
-# The regression MUST have this label
-required-issue-label = "regression-from-stable-to-beta"
-# if the above conditions matches, the PR will receive these labels
-add-labels = ["beta-nominated"]
-
-[backport.t-compiler-stable-backport]
-required-pr-labels = ["T-compiler"]
-required-issue-label = "regression-from-stable-to-stable"
-add-labels = ["stable-nominated"]
 
 # ------------------------------------------------------------------------------
 # Ping groups