Removed additional colon in SaveAs dialog

[robece]

Fixes #2440 - Include a terse summary of the change or which issue is fixed.

This small change is related to the closed issue:
#2440

Pull Request checklist:

• I've named my PR in the form of "Fixes #issue. Terse description."
• My code follows the style guidelines of Terminal.Gui - if you use Visual Studio, hit CTRL-K-D to automatically reformat your files before committing.
• My code follows the Terminal.Gui library design guidelines
• I ran dotnet test before commit
• I have made corresponding changes to the API documentation (using /// style comments)
• My changes generate no new warnings
• I have checked my code and corrected any poor grammar or misspellings
• I conducted basic QA to assure all features are working

[BDisp]

@robece after the Fixes you have to put the #issue. The way you did it you are referencing the wrong issue.

[robece]

@robece after the Fixes you have to put the #issue. The way you did it you are referencing the wrong issue.

Fixed. Thanks!

[tig]

Thanks!