triagebot: add reminder for library/core/src/unicode/unicode_data.rs that it needs to be generated by tool

And should not be directly edited.

Author: jieyouxu

triagebot.toml

@@ -674,6 +674,15 @@ instead.
 """
 cc = ["@calebzulawski", "@programmerjake"]
 
+[mentions."library/core/src/unicode/unicode_data.rs"]
+message = """
+`library/core/src/unicode/unicode_data.rs` is generated by
+`src/tools/unicode-table-generator` via `./x run
+src/tools/unicode-table-generator`. If you want to modify `unicode_data.rs`,
+please modify the tool then regenerate the library source file with the tool
+instead of editing the library source file manually.
+"""
+
 [mentions."src/librustdoc/clean/types.rs"]
 cc = ["@camelid"]