change config.toml to bootstrap.toml for bootstrap module

INSTALL.md

@@ -6,9 +6,9 @@ If you just want to install Rust, check out the [README.md](README.md) instead.*
 
 The Rust build system uses a Python script called `x.py` to build the compiler,
 which manages the bootstrapping process. It lives at the root of the project.
-It also uses a file named `config.toml` to determine various configuration
+It also uses a file named `bootstrap.toml` to determine various configuration
 settings for the build. You can see a full list of options in
-`config.example.toml`.
+`bootstrap.example.toml`.
 
 The `x.py` command can be run directly on most Unix systems in the following
 format:
@@ -115,7 +115,7 @@ See [the rustc-dev-guide for more info][sysllvm].
 
 This project provides a configure script and makefile (the latter of which just
 invokes `x.py`). `./configure` is the recommended way to programmatically
-generate a `config.toml`. `make` is not recommended (we suggest using `x.py`
+generate a `bootstrap.toml`. `make` is not recommended (we suggest using `x.py`
 directly), but it is supported and we try not to break it unnecessarily.
 
 ```sh
@@ -123,7 +123,7 @@ directly), but it is supported and we try not to break it unnecessarily.
 make && sudo make install
 ```
 
-`configure` generates a `config.toml` which can also be used with normal `x.py`
+`configure` generates a `bootstrap.toml` which can also be used with normal `x.py`
 invocations.
 
 ## Building on Windows
@@ -255,7 +255,7 @@ Windows build triples are:
     - `x86_64-pc-windows-msvc`
 
 The build triple can be specified by either specifying `--build=<triple>` when
-invoking `x.py` commands, or by creating a `config.toml` file (as described in
+invoking `x.py` commands, or by creating a `bootstrap.toml` file (as described in
 [Building on a Unix-like system](#building-on-a-unix-like-system)), and passing
 `--set build.build=<triple>` to `./configure`.