restrict const-eval-related 'content' triggers to library/ folder

triagebot.toml

diff --git a/triagebot.toml b/triagebot.toml
index 262ea3a..a161f7c 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -1476,6 +1476,7 @@
 
 [mentions."#[miri::intrinsic_fallback_is_spec]"]
 type = "content"
+trigger_files = ["library"]
 message = """
 ⚠️ `#[miri::intrinsic_fallback_is_spec]` must only be used if the function actively checks for all UB cases,
 and explores the possible non-determinism of the intrinsic.
@@ -1484,6 +1485,7 @@
 
 [mentions."#[rustc_allow_const_fn_unstable"]
 type = "content"
+trigger_files = ["library"]
 message = """
 ⚠️ `#[rustc_allow_const_fn_unstable]` needs careful audit to avoid accidentally exposing unstable
 implementation details on stable.
@@ -1492,6 +1494,7 @@
 
 [mentions."#[rustc_intrinsic_const_stable_indirect]"]
 type = "content"
+trigger_files = ["library"]
 message = """
 ⚠️ `#[rustc_intrinsic_const_stable_indirect]` controls whether intrinsics can be exposed to stable const
 code; adding it needs t-lang approval.