docs: document ThrowsAsync

[vbreuss]

This PR adds documentation for the ThrowsAsync method and standardizes markdown heading levels across documentation files.

Changes:

• Documents the ThrowsAsync method for async method setups alongside ReturnsAsync
• Converts bold text headers to proper markdown heading levels (##, ###, ####) for better document structure
• Provides example usage showing sequential behavior with ReturnsAsync, ThrowsAsync, and Forever()

---

• Fixes Document async exception handling with ThrowsAsync #425

[Copilot]

Pull request overview

This PR adds documentation for the ThrowsAsync method and standardizes markdown heading levels across documentation files.

Changes:

• Documents the ThrowsAsync method for async method setups alongside ReturnsAsync
• Converts bold text headers to proper markdown heading levels (##, ###, ####) for better document structure
• Provides example usage showing sequential behavior with ReturnsAsync, ThrowsAsync, and Forever()

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
README.md	Added ThrowsAsync documentation and example showing sequential async method setup behavior
Docs/pages/special-types/02-delegates.md	Converted "Setup" and "Verification" from bold text to proper ## headings
Docs/pages/setup/04-parameter-matching.md	Converted section headers from bold text to proper ### and #### markdown headings
Docs/pages/setup/02-methods.md	Converted "Async Methods" to ## heading and documented ThrowsAsync with example
Docs/pages/setup/01-properties.md	Converted "Initialization", "Returns / Throws", and "Callbacks" from bold text to ## headings
Docs/pages/01-create-mocks.md	Converted "MockBehavior options" from bold text to ### heading

[github-actions]

🚀 Benchmark Results

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.3 LTS (Noble Numbat)

AMD EPYC 7763 3.17GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.102

[Host] : .NET 10.0.2 (10.0.2, 10.0.225.61305), X64 RyuJIT x86-64-v3
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Method	Mean	Error	StdDev	Gen0	Gen1	Allocated
Simple_Mockolate	1.546 μs	0.0085 μs	0.0075 μs	0.2270	-	3.73 KB
Simple_Moq	181.742 μs	0.6245 μs	0.5536 μs	0.4883	-	14.55 KB
Simple_NSubstitute	5.739 μs	0.0183 μs	0.0162 μs	0.5569	0.0076	9.14 KB
Simple_FakeItEasy	6.265 μs	0.0101 μs	0.0084 μs	0.4959	-	8.11 KB

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Test Results

    21 files  ±0      21 suites  ±0   6m 4s ⏱️ -6s
 2 517 tests ±0   2 516 ✅ ±0  1 💤 ±0  0 ❌ ±0 
16 800 runs  ±0  16 799 ✅ ±0  1 💤 ±0  0 ❌ ±0 

Results for commit d2ca323. ± Comparison against base commit 6937827.

[github-actions]

This is addressed in release v1.1.0.