Do not include heavy Japanese tokenizer by default

Author: valeriansaliou

Cargo.toml

@@ -50,7 +50,7 @@ tikv-jemallocator = { version = "0.4", optional = true }
 winapi = { version = "0.3", features = ["minwindef", "consoleapi"] }
 
 [features]
-default = ["allocator-jemalloc", "tokenizer-chinese", "tokenizer-japanese"]
+default = ["allocator-jemalloc", "tokenizer-chinese"]
 allocator-jemalloc = ["tikv-jemallocator"]
 tokenizer-chinese = ["jieba-rs"]
 tokenizer-japanese = ["lindera-core", "lindera-dictionary", "lindera-tokenizer"]

README.md

@@ -75,6 +75,8 @@ You can find the built binaries in the `./target/release` directory.
 
 _Install `build-essential`, `clang`, `libclang-dev`, `libc6-dev`, `g++` and `llvm-dev` to be able to compile the required RocksDB dependency._
 
+Note that the following optional features can be enabled upon building Sonic: `allocator-jemalloc`, `tokenizer-chinese` and `tokenizer-japanese` (some might be already enabled by default).
+
 **👉 Install from Cargo:**
 
 You can install Sonic directly with `cargo install`: