Improve IME area reporting and set IME area in `TextArea` #2411

Job	Run time
cargo check (msrv) (windows-latest)	1m 27s
cargo clippy (windows-latest)	4m 58s
cargo check (aarch64-android)	21s
cargo check (msrv) (wasm32)	15s
cargo check (msrv) (macos-latest)	34s
cargo clippy (macos-latest)	2m 2s
cargo check (msrv) (ubuntu-latest)	38s
cargo clippy (ubuntu-latest)	3m 27s
cargo clippy (wasm32)	1m 55s
cargo doc	40s
formatting	31s
Prime LFS Cache	7s
cargo test (wasm32)	20s
typos	5s
cargo test (windows-latest)	3m 42s
cargo test (macos-latest)	1m 36s
cargo test (ubuntu-latest)	3m 39s
	26m 17s

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