feat: add required filters and assertions for fields

[vbreuss]

Add a WhichAreRequired filter and IsRequired / AreRequired assertions (plus negated variants) for FieldInfo, matching what already exists for properties.

---

• Fixes Required filter/assertions for fields #339

[github-actions]

Test Results

    13 files  ±  0      13 suites  ±0   9m 50s ⏱️ +11s
 6 696 tests + 24   6 693 ✅ + 24   3 💤 ±0  0 ❌ ±0 
40 021 runs  +144  40 008 ✅ +144  13 💤 ±0  0 ❌ ±0 

Results for commit fd4f6e6. ± Comparison against base commit 4079331.

[github-actions]

🚀 Benchmark Results

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.4 LTS (Noble Numbat)

AMD EPYC 7763 2.78GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.300

[Host]     : .NET 10.0.8 (10.0.8, 10.0.826.23019), X64 RyuJIT x86-64-v3

DefaultJob : .NET 10.0.8 (10.0.8, 10.0.826.23019), X64 RyuJIT x86-64-v3

Method	Mean	Error	StdDev	Gen0	Allocated
TypeIsNotStatic_aweXpect	221.9 ns	3.97 ns	3.72 ns	0.0386	648 B

[github-actions]

👽 Mutation Results

aweXpect.Reflection

Details

File	Score	Killed	Survived	Timeout	No Coverage	Ignored	Compile Errors	Total Detected	Total Undetected	Total Mutants
Filters/FieldFilters.WhichAreRequired.cs	100.00%	3	0	0	0	0	0	3	0	3
Helpers/FieldInfoHelpers.cs	97.14%	34	1	0	0	12	2	34	1	49
ThatField.IsRequired.cs	100.00%	10	0	0	0	3	6	10	0	19
ThatFields.AreRequired.cs	100.00%	18	0	0	0	4	12	18	0	34

The final mutation score is 98.48%

Coverage Thresholds: high:80 low:60 break:0

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
8.3% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

This is addressed in release v2.0.0.