String constructor doesn't actually always return a new string

### Type of issue

Missing information

### Description

https://dotnetfiddle.net/rATujf

https://learn.microsoft.com/en-us/dotnet/api/system.string.-ctor?view=net-8.0#system-string-ctor(system-char()) says "Initializes a new instance". But the above sample shows that isn't always true.

### Page URL

https://learn.microsoft.com/en-us/dotnet/api/system.string.-ctor?view=net-8.0

### Content source URL

https://github.com/dotnet/dotnet-api-docs/blob/main/xml/System/String.xml

### Document Version Independent Id

90baab9e-9ef3-9bb5-d433-8d861d7fa876

### Article author

@dotnet-bot