prevent trashing when building with rustc in Jetbrains IDEs.

For the IDE to discover what's going on, it will use hidden environment variables
to perform the build with, but that also affects certain crates which then report
they changed.

If this is intermixed with actual nightly builds, unnecessary rebuilds happen all the time.
To prevent this, just use `nightly` by default without actually using nightly features.

.github/actions/init-env-rust/action.yaml

@@ -3,16 +3,6 @@ description: prepare runner for rust related tasks
 runs:
   using: "composite"
   steps:
-    - name: Setup Nightly
-      if: runner.os == 'Windows'
-      shell: bash
-      run: |
-         mv rust-toolchain.toml.windows rust-toolchain.toml
-    - name: Setup Stable
-      if: runner.os != 'Windows'
-      shell: bash
-      run: |
-         mv rust-toolchain.toml.stable rust-toolchain.toml
     - name: Check versions
       shell: bash
       run: |

DEVELOPMENT.md

@@ -164,8 +164,10 @@ Building on Windows is a bit of a tricky process. Here are some helpful tips.
 
 #### Nightly Compiler
 
-As a few crates require nightly features on Windows, it's easiest to set an override
+As a few crates require nightly features on Windows, a `rust-toolchain.toml` is provided
-to automatically use a nightly compiler.
+to have rustup use the right compiler version.
+
+If for some reason this cannot be used or doesn't kick-in, one can also set an override.
 
 ```shell
 rustup override add nightly-2024-07-01

rust-toolchain.toml.stable

@@ -1,4 +0,0 @@
-[toolchain]
-channel = "stable"
-components = [ "rustfmt", "clippy" ]
-profile = "minimal"