related to
- nushell/nushell#11365
- amtoine/nu-git-manager#154

## description
this PR will suppress the deprecation warning from
nushell/nushell#11365 which is deprecating `:
bool` annotations for switches.

this didn't break anything but did show a bunch of spurious deprecation
warnings in CI for instance:
https://github.com/amtoine/nu-git-manager/actions/runs/7307569422/job/19913395508#step:6:17

related to
- nushell/nushell#11365

## description
this PR will suppress the deprecation warning from
nushell/nushell#11365 which is deprecating `:
bool` annotations for switches

related to
- nushell/nushell#11365

related to
- nushell/nushell#11365

## description
this PR will suppress the deprecation warning from
nushell/nushell#11365 which is deprecating `:
bool` annotations for switches

# Description
This is a follow up to: #11365

After this pr, `--flag: bool` is no longer allowed.

I think `ParseWarning::Deprecated` is useful when we want to deprecated
something at syntax level, so I just leave it there for now.

# User-Facing Changes
## Before
```
❯ def foo [--b: bool] {}
Error:   × Deprecated: --flag: bool
   ╭─[entry #15:1:1]
 1 │ def foo [--b: bool] {}
   ·               ──┬─
   ·                 ╰── `--flag: bool` is deprecated and will be removed in 0.90. Please use `--flag` instead, more info: https://www.nushell.sh/book/custom_commands.html
   ╰────
```

## After
```
❯ def foo [--b: bool] {}
Error:   × Type annotations are not allowed for boolean switches.
   ╭─[entry #2:1:1]
 1 │ def foo [--b: bool] {}
   ·               ──┬─
   ·                 ╰── Remove the `: bool` type annotation.
   ╰────
```
# Tests + Formatting
Done

# Description
While nushell#11057 is merged, it's hard to tell the difference between
`--flag: bool` and `--flag`, and it makes user hard to read custom
commands' signature, and hard to use them correctly.

After discussion, I think we can deprecate `--flag: bool` usage, and
encourage using `--flag` instead.

# User-Facing Changes
The following code will raise warning message, but don't stop from
running.
```nushell
❯ def florb [--dry-run: bool, --another-flag] { "aaa" };  florb
Error:   × Deprecated: --flag: bool
   ╭─[entry nushell#7:1:1]
 1 │ def florb [--dry-run: bool, --another-flag] { "aaa" };  florb
   ·                       ──┬─
   ·                         ╰── `--flag: bool` is deprecated. Please use `--flag` instead, more info: https://www.nushell.sh/book/custom_commands.html
   ╰────

aaa
```

cc @kubouch 

# Tests + Formatting
Done

# After Submitting
- [ ] Add more information under
https://www.nushell.sh/book/custom_commands.html to indicate `--dry-run:
bool` is not allowed,
- [ ] remove `: bool` from custom commands between 0.89 and 0.90

---------

Co-authored-by: Antoine Stevan <44101798+amtoine@users.noreply.github.com>

# Description
This is a follow up to: nushell#11365

After this pr, `--flag: bool` is no longer allowed.

I think `ParseWarning::Deprecated` is useful when we want to deprecated
something at syntax level, so I just leave it there for now.

# User-Facing Changes
## Before
```
❯ def foo [--b: bool] {}
Error:   × Deprecated: --flag: bool
   ╭─[entry nushell#15:1:1]
 1 │ def foo [--b: bool] {}
   ·               ──┬─
   ·                 ╰── `--flag: bool` is deprecated and will be removed in 0.90. Please use `--flag` instead, more info: https://www.nushell.sh/book/custom_commands.html
   ╰────
```

## After
```
❯ def foo [--b: bool] {}
Error:   × Type annotations are not allowed for boolean switches.
   ╭─[entry nushell#2:1:1]
 1 │ def foo [--b: bool] {}
   ·               ──┬─
   ·                 ╰── Remove the `: bool` type annotation.
   ╰────
```
# Tests + Formatting
Done