This PR closes [Issue
#13482](https://github.com/nushell/nushell/issues/13482)
# Description
This PR tend to make all math function to be constant.
# User-Facing Changes
The math commands now can be used as constant methods.
### Some Example
```
> const MODE = [3 3 9 12 12 15] | math mode
> $MODE
╭───┬────╮
│ 0 │ 3 │
│ 1 │ 12 │
╰───┴────╯
> const LOG = [16 8 4] | math log 2
> $LOG
╭───┬──────╮
│ 0 │ 4.00 │
│ 1 │ 3.00 │
│ 2 │ 2.00 │
╰───┴──────╯
> const VAR = [1 3 5] | math variance
> $VAR
2.6666666666666665
```
# Tests + Formatting
Tests are added for all of the math command to test there constant
behavior.
I mostly focused on the actual user experience, not the correctness of
the methods and algorithms.
# After Submitting
I think this change don't require any additional documentation. Feel
free to correct me in this topic please.
# Description
This PR tights input/output type-checking a bit more. There are a lot of
commands that don't have correct input/output types, so part of the
effort is updating them.
This PR now contains updates to commands that had wrong input/output
signatures. It doesn't add examples for these new signatures, but that
can be follow-up work.
# User-Facing Changes
BREAKING CHANGE BREAKING CHANGE
This work enforces many more checks on pipeline type correctness than
previous nushell versions. This strictness may uncover incompatibilities
in existing scripts or shortcomings in the type information for internal
commands.
# Tests + Formatting
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# After Submitting
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# Description
Before this PR, `math round` ignores the input if it's an `int`. This
results in the following behaviour:
```
> 123 | math round --precision -1
123
```
When the correct result is 120.
Now `int values` are converted to `float values` before actually
rounding up the number in order to take advantage of the float
implementation.
Fixes#9049.
