Add word count for markdown and plain text files

[saahityaedams]

Release Notes:

• Added word count for markdown and plain text files

[saahityaedams]

I fixed the merge conflicts and squashed the changes into a single commit from this PR: #22601 @mikayla-maki

[mikayla-maki]

Thank you!

[saahityaedams]

I just looked at the CI logs and see some errors (The first 2 don't seem related to PR, the last one slightly related in the sense of being in the same crate I made changes to). Looking into it.

2025-01-03T04:15:21.1093820Z �[0m
2025-01-03T04:15:21.1094910Z �[31;1m────�[0m �[31;1mSTDERR:            �[0m �[35;1mzed::bin/zed�[0m �[36mzed::tests�[0m�[36m::�[0m�[34;1mtest_navigation�[0m
2025-01-03T04:15:21.1097200Z [2025-01-03T04:15:19Z ERROR settings] Failed to write settings to file "/Users/administrator/.config/zed/settings.json"
2025-01-03T04:15:21.1097910Z     
2025-01-03T04:15:21.1098140Z     Caused by:
2025-01-03T04:15:21.1098520Z         not found: /Users/administrator/.config/zed

2025-01-03T04:15:21.1223400Z [2025-01-03T04:15:20Z ERROR theme] theme not found: One Light

2025-01-03T04:15:21.1340650Z �[0m�[31;1mthread 'zed::tests::test_navigation' panicked at /Users/administrator/actions-runner-3/_work/zed/zed/crates/settings/src/settings_store.rs:341:32:�[0m
2025-01-03T04:15:21.1342210Z �[31;1munregistered setting type go_to_line::cursor_position::LineIndicatorFormat�[0m