Auto merge of #137081 - Shourya742:2025-02-15-change-config.toml-to-bootstrap.toml, r=onur-ozkan,jieyouxu,kobzol

change config.toml to bootstrap.toml

Currently, both Bootstrap and Cargo uses same name as their configuration file, which can be confusing. This PR is based on a discussion to rename `config.toml` to `bootstrap.toml` for Bootstrap. Closes: #126875.

I have split the PR into atomic commits to make it easier to review. Once the changes are finalized, I will squash them. I am particularly concerned about the changes made to modules that are not part of Bootstrap. How should we handle those changes? Should we ping the respective maintainers?

Author: bors

.github/ISSUE_TEMPLATE/bootstrap.md

@@ -32,7 +32,7 @@ Describe what you expected to happen.
 Describe what actually happened.
 -->
 
-### Bootstrap configuration (config.toml)
+### Bootstrap configuration (bootstrap.toml)
 ```toml
 <config>
 ```

.gitignore

@@ -1,6 +1,6 @@
 # This file should only ignore things that are generated during a `x.py` build,
 # generated by common IDEs, and optional files controlled by the user that
-# affect the build (such as config.toml).
+# affect the build (such as bootstrap.toml).
 # In particular, things like `mir_dump` should not be listed here; they are only
 # created during manual debugging and many people like to clean up instead of
 # having git ignore such leftovers. You can use `.git/info/exclude` to
@@ -34,6 +34,7 @@ Session.vim
 !/tests/run-make/thumb-none-qemu/example/.cargo
 
 ## Configuration
+/bootstrap.toml
 /config.toml
 /Makefile
 config.mk