Fix text selection of only whitespace #12742

Job	Run time
Check wasm32+atomics	1m 34s
android	24s
Check wasm32 + wasm-bindgen	2m 20s
cargo-deny aarch64-apple-darwin	37s
Format + check + test	5m 32s
cargo-deny aarch64-linux-android	38s
ios	27s
Check Windows	1m 54s
cargo-deny i686-pc-windows-gnu	36s
cargo-deny i686-pc-windows-msvc	38s
cargo-deny i686-unknown-linux-gnu	37s
cargo-deny wasm32-unknown-unknown	44s
cargo-deny x86_64-apple-darwin	43s
cargo-deny x86_64-pc-windows-gnu	39s
cargo-deny x86_64-pc-windows-msvc	37s
cargo-deny x86_64-unknown-linux-gnu	38s
cargo-deny x86_64-unknown-linux-musl	40s
cargo-deny x86_64-unknown-redox	42s
	20m 0s

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