IDE0057 simplify substring

[gerhardol]

Proposed changes

VS suggested change, simplifies displayed code using range operator.
(Should be no change to runtime execution.)

https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/style-rules/ide0057

Typical like

diff --git a/BugReporter/GitHubUrlBuilder.cs b/BugReporter/GitHubUrlBuilder.cs
index 8377b..5b8b8 100644
--- a/BugReporter/GitHubUrlBuilder.cs
+++ b/BugReporter/GitHubUrlBuilder.cs
@@ -46,7 +46,7 @@ public GitHubUrlBuilder(IErrorReportUrlBuilder errorReportUrlBuilder)
             if (subject.Length > 69)
             {
                 // if the subject is longer than 70 characters, trim it
-                subject = subject.Substring(0, 66) + "...";
+                subject = subject[..66] + "...";
             }
 
             string urlEncodedError = _errorReportUrlBuilder.Build(exception, exceptionInfo, environmentInfo, additionalInfo);

Test methodology

Refactoring

Merge strategy

I agree that the maintainer squash merge this PR (if the commit message is clear).

---

✒️ I contribute this code under The Developer Certificate of Origin.

[RussKie]

I'm not used to this syntax, but I'm not going to stand in the way of progress :)