ICU-23437 Lookahead colouring

[eggrobin]

TODO: Please describe your changes here.

Checklist

• Required: Issue filed: ICU-23437
• Required: The PR title must be prefixed with a JIRA Issue number. Example: "ICU-NNNNN Fix xyz"
• Required: Each commit message must be prefixed with a JIRA Issue number. Example: "ICU-NNNNN Fix xyz"
• Issue accepted (done by Technical Committee after discussion)
• Tests included, if applicable
• API docs and/or User Guide docs changed or added, if applicable
• Approver: Feel free to merge on my behalf

[jira-pull-request-webhook]

Notice: the branch changed across the force-push!

• icu4c/source/.clang-format is no longer changed in the branch
• icu4c/source/common/rbbiscan.cpp is no longer changed in the branch
• icu4c/source/common/rbbitblb.cpp is different
• icu4c/source/data/brkitr/rules/line_cj.txt is no longer changed in the branch
• icu4c/source/data/brkitr/rules/line_loose_cj.txt is no longer changed in the branch
• icu4c/source/data/brkitr/rules/line_loose_phrase_cj.txt is no longer changed in the branch
• icu4c/source/data/brkitr/rules/line_loose.txt is no longer changed in the branch
• icu4c/source/data/brkitr/rules/line_normal_cj.txt is no longer changed in the branch
• icu4c/source/data/brkitr/rules/line_normal_phrase_cj.txt is no longer changed in the branch
• icu4c/source/data/brkitr/rules/line_normal.txt is no longer changed in the branch
• icu4c/source/data/brkitr/rules/line_phrase_cj.txt is no longer changed in the branch
• icu4c/source/data/brkitr/rules/line.txt is no longer changed in the branch
• icu4c/source/data/brkitr/rules/uline.txt is no longer changed in the branch
• icu4c/source/test/intltest/rbbitst.cpp is no longer changed in the branch
• icu4c/source/test/intltest/rbbitst.h is no longer changed in the branch
• icu4c/source/test/testdata/rbbitst.txt is no longer changed in the branch

View Diff Across Force-Push

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