modify config.toml->bootstrap.toml for new upstream changes

compiler/rustc_session/src/options.rs

@@ -389,7 +389,7 @@ top_level_options!(
         ///
         /// This directory is what the virtual `/rustc/$hash` is translated back to,
         /// if Rust was built with path remapping to `/rustc/$hash` enabled
-        /// (the `rust.remap-debuginfo` option in `config.toml`).
+        /// (the `rust.remap-debuginfo` option in `bootstrap.toml`).
         real_rust_source_base_dir: Option<PathBuf> [TRACKED_NO_CRATE_HASH],
 
         edition: Edition [TRACKED],

src/bootstrap/src/core/download.rs

@@ -845,7 +845,7 @@ download-rustc = false
     HELP: There could be two reasons behind this:
         1) The host triple is not supported for `download-ci-gcc`.
         2) Old builds get deleted after a certain time.
-    HELP: In either case, disable `download-ci-gcc` in your config.toml:
+    HELP: In either case, disable `download-ci-gcc` in your bootstrap.toml:
 
     [gcc]
     download-ci-gcc = false

src/bootstrap/src/utils/cc_detect.rs

@@ -122,7 +122,7 @@ pub fn find(build: &Build) {
 
 /// Probes and configures the C and C++ compilers for a single target.
 ///
-/// This function uses both user-specified configuration (from `config.toml`) and auto-detection
+/// This function uses both user-specified configuration (from `bootstrap.toml`) and auto-detection
 /// logic to determine the correct C/C++ compilers for the target. It also determines the appropriate
 /// archiver (`ar`) and sets up additional compilation flags (both handled and unhandled).
 pub fn find_target(build: &Build, target: TargetSelection) {
@@ -186,7 +186,7 @@ pub fn find_target(build: &Build, target: TargetSelection) {
 }
 
 /// Determines the default compiler for a given target and language when not explicitly
-/// configured in `config.toml`.
+/// configured in `bootstrap.toml`.
 fn default_compiler(
     cfg: &mut cc::Build,
     compiler: Language,

src/bootstrap/src/utils/change_tracker.rs

@@ -387,7 +387,7 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
     },
     ChangeInfo {
         change_id: 137081,
-        severity: ChangeSeverity::Info,
+        severity: ChangeSeverity::Warning,
         summary: "The default configuration filename has changed from `config.toml` to `bootstrap.toml`. `config.toml` is deprecated but remains supported for backward compatibility.",
     },
 ];