feat!: 5 new commands to toggle text between PascalCase, camelCase, snake_case, Title Case and kebab-case

[nik-rev]

This PR introduces a new mode under ` called "case" mode which has several utility key mappings for working with switching case of text

switch_case, switch_to_lowercase and switch_to_uppercase have been moved to this new mode. 5 new commands have been added and are accessible under ` as well:

Key	Description	Command
`l	Switch text to lowercase	switch_to_lowercase
`u	Switch text to UPPERCASE	switch_to_uppercase
`p	Switch text to PascalCase	switch_to_pascal_case
`c	Switch text to camelCase	switch_to_camel_case
`t	Switch text to Title Case	switch_to_title_case
`s	Switch text to snake_case	switch_to_snake_case
`k	Switch text to kebab-case	switch_to_kebab_case
`a	Switch text to aLTERNATE cASE	switch_to_alternate_case

Closes #5197

---

Unlike #4615 this PR doesn't pull in any extra dependencies. It builds on top of the existing case_conversion.rs module and adds many tests to make sure that functionality is correct. The tests even fixed some edges with the existing camelCase implementation

Breaking changes

Remaps several keys:

old	new
Alt-`	`u
`	`l

Renames a command:

old	new
switch_case	switch_to_alternate_case

[nik-rev]

Interesting feature idea, however, I'm a bit unsure if this might be more suitable as a plugin than as a core feature.

Imo, it shouldn't be a plugin. This is a useful feature that is handy to have in an editor when you need it, but it's not something you know you need until you need it.

[nik-rev]

Interesting feature idea, however, I'm a bit unsure if this might be more suitable as a plugin than as a core feature.

Btw, I only replied now because your reply was marked as "off topic" before

How do comments get marked as off-topic? Is it automatic ,or someone marked yours?

[TornaxO7]

How do comments get marked as off-topic?

You can mark your own comments as off-topic but I also think that the repo owners are able to mark comments as offtopic as well.

Is it automatic ,or someone marked yours?

I did it myself because I thought that my comment there might be not that "helpful" so I just marked it as "offtopic", just to be safe :)

[gabydd]

We have case conversion in helix core from the snippets system which should be used instead of another dependency https://github.com/helix-editor/helix/blob/master/helix-core%2Fsrc%2Fcase_conversion.rs

[darshanCommits]

Hopefully this gets merged, now that it's not even pulling dep.

[nik-rev]

I added back the ~ mapping, as I realized it's too much of a breaking change to remove it (Vim had it for decades, and Helix...). It's okay to have 2 keys that do the same thing, e.g. we have Ctrl-c and Space-c