Rollup merge of #151043 - patch-1, r=ehuss
armv7-unknown-linux-uclibceabihf.md: Fix bootstrap.toml syntax
With the suggested value we were getting instead:
```
ERROR: Failed to parse '/tmp/rust/bootstrap.toml': unknown field `stage`, expected one of `build`, `description`, `host`, `target`, `build-dir`, `cargo`, `rustc`, `rustfmt`, `cargo-clippy`, `docs`, `compiler-docs`, `library-docs-private-items`, `docs-minification`, `submodules`, `gdb`, `lldb`, `nodejs`, `npm`, `yarn`, `python`, `windows-rc`, `reuse`, `locked-deps`, `vendor`, `full-bootstrap`, `bootstrap-cache-path`, `extended`, `tools`, `tool`, `verbose`, `sanitizers`, `profiler`, `cargo-native-static`, `low-priority`, `configure-args`, `local-rebuild`, `print-step-timings`, `print-step-rusage`, `check-stage`, `doc-stage`, `build-stage`, `test-stage`, `install-stage`, `dist-stage`, `bench-stage`, `patch-binaries-for-nix`, `metrics`, `android-ndk`, `optimized-compiler-builtins`, `jobs`, `compiletest-diff-tool`, `compiletest-allow-stage0`, `compiletest-use-stage0-libtest`, `tidy-extra-checks`, `ccache`, `exclude` for key `build`
```
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