Fix build error with syntect 4.7.0

[taiki-e]

Fixes #1991

[taiki-e]

If the dump-load (or dump-load-rs) feature is not specified, the following error is happen. It seems another bug of syntect.

error[E0425]: cannot find function `from_reader` in module `crate::dumps`
   --> /Users/taiki/.cargo/registry/src/github.com-1ecc6299db9ec823/syntect-4.7.0/src/parsing/syntax_set.rs:432:23
    |
432 |         crate::dumps::from_reader(data).expect("data is not corrupt or out of sync with the code")
    |                       ^^^^^^^^^^^ not found in `crate::dumps`
    |
help: consider importing one of these items
    |
1   | use plist::from_reader;
    |
1   | use serde_json::from_reader;
    |

For more information about this error, try `rustc --explain E0425`.

[taiki-e]

Ah, this seems to be a breaking change introduced in trishume/syntect#393.

https://github.com/trishume/syntect/blob/b4e2cbb280c79cc5a3b3c12f342d6b792f905001/Cargo.toml#L62-L64

# If you enable "parsing", you must also enable either "dump-load" or
# "dump-load-rs", and "dump-create" or "dump-create-rs". Otherwise the code that
# enables lazy-loading of syntaxes will not compile.

[taiki-e]

It seems tests are failing due to OOM.

https://github.com/sharkdp/bat/runs/4636833103?check_suite_focus=true

running 44 tests
test assets::build_assets::acknowledgements::tests::test_append_to_acknowledgements_adds_newline_if_missing ... ok
test assets::build_assets::acknowledgements::tests::test_normalize_license_text ... ok
test assets::build_assets::acknowledgements::tests::test_normalize_license_text_with_windows_line_endings ... ok
memory allocation of 7881122326526296064 bytes failederror: test failed, to rerun pass '--lib'

Caused by:
  process didn't exit successfully: `/home/runner/work/bat/bat/target/debug/deps/bat-5f7ebdce0ebb4f19` (signal: 6, SIGABRT: process abort signal)

[taiki-e]

closing -- syntect 4.7.0 has been yanked: trishume/syntect#402 (comment)

[sharkdp]

Thank you anyway for taking a stab at this!