High precision atan, sin, cos, and other related functions

[Safari77]

$ time ./target/debug/fend "tan(atan(1e320))"
approx. 100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

real 0m0,004s
user 0m0,002s
sys 0m0,004s

[Safari77]

iter_root_n precision fix to use INTERNAL_PRECISION.
Each iteration adds 1 bit of precision.
Since log2(10) ≈ 3.32, we need ~3.32 iterations per decimal digit. Use 3.35 as safety factor.

	fn iter_root_n<I: Interrupt>(
		mut low_bound: Self,
		val: &Self,
		n: &Self,
		int: &I,
	) -> FResult<Self> {
		let mut high_bound = low_bound.clone().add(1.into(), int)?;
		let iterations = ((Self::INTERNAL_PRECISION as f64) * 3.35) as usize;
		for _ in 0..iterations {
			let guess = low_bound
				.clone()
				.add(high_bound.clone(), int)?
				.div(&2.into(), int)?;
			if &guess.clone().pow(n.clone(), int)?.value < val {
				low_bound = guess;
			} else {
				high_bound = guess;
			}
		}
		low_bound.add(high_bound, int)?.div(&2.into(), int)
	}

(it would be preferred if 'dp' parameter was available here)

[codecov]

Codecov Report

❌ Patch coverage is 96.67969% with 17 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.15%. Comparing base (9636b16) to head (a619f73).
⚠️ Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
core/src/num/bigrat.rs	96.60%	17 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #374      +/-   ##
==========================================
+ Coverage   81.47%   82.15%   +0.68%     
==========================================
  Files          52       52              
  Lines       14717    15484     +767     
==========================================
+ Hits        11990    12721     +731     
- Misses       2727     2763      +36     

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[Safari77]

added num-traits = "0.2.19" because clippy was being pedantic.
Changed that iter_root_n to use configurable precision.