Rephrase Notes section and fix markdown (#996)

I guess it is https://dotnet.github.io/docfx/spec/docfx_flavored_markdown.html?tabs=tabid-1%2Ctabid-a#note-warningtipimportant to blame for abstract self-contradictory samples with copy-paste artifacts.

docs/articles/contributing/documentation.md

@@ -15,37 +15,37 @@ BenchmarkDotNet uses [DocFX](https://dotnet.github.io/docfx/) as a documentation
 
 ## Notes
 
-DocFX uses the following syntax for different types of notes:
+DocFX uses the [following syntax](https://dotnet.github.io/docfx/spec/docfx_flavored_markdown.html?tabs=tabid-1%2Ctabid-a#note-warningtipimportant) inside block quote for different types of notes:
 
 ```markdown
 > [!NOTE]
-> <note content>
+> note content
 > [!TIP]
-> <note content>
+> tip content
 > [!WARNING]
-> <warning content>
+> warning content
 > [!IMPORTANT]
-> <important content>
+> important content
 > [!Caution]
-> <caution content>
+> caution content
 ```
 
 It will be transformed to:
 
 > [!NOTE]
-> <note content>
+> note content
 
 > [!TIP]
-> <note content>
+> tip content
 
 > [!WARNING]
-> <warning content>
+> warning content
 
 > [!IMPORTANT]
-> <important content>
+> important content
 
 > [!Caution]
-> <caution content>
+> caution content
 
 ## Building documentation locally
 
@@ -78,4 +78,4 @@ Linux/macOS (Bash):
 
 * [DocFX User Manual](https://dotnet.github.io/docfx/tutorial/docfx.exe_user_manual.html)
 * [DocFX Tutorials: Links and Cross References](https://dotnet.github.io/docfx/tutorial/links_and_cross_references.html)
-* [DocFX Flavored Markdown](https://dotnet.github.io/docfx/spec/docfx_flavored_markdown.html?tabs=tabid-1%2Ctabid-a#file-inclusion)
+* [DocFX Flavored Markdown](https://dotnet.github.io/docfx/spec/docfx_flavored_markdown.html?tabs=tabid-1%2Ctabid-a#file-inclusion)