docs: fix FSharp.Core->FSharpLint.Core typo (#761)

Update the 'Running Lint From An Application' documentation to say install FSharpLint.Core
rather than FSharp.Core, because as it stands, the text says 'FSharp.Core' but the link goesç
to FSharpLint.Core, and it looks like they should both say FSharpLint.Core.

Author: Numpsy

docs/content/index.md

@@ -107,7 +107,7 @@ Rules can be disabled within the code using structured comments. See the [Suppre
 
 ## Running Lint From An Application
 
-Install the [`FSharp.Core` nuget package](https://www.nuget.org/packages/FSharpLint.Core/).
+Install the [`FSharpLint.Core` nuget package](https://www.nuget.org/packages/FSharpLint.Core/).
 
 The namespace `FSharpLint.Application` contains a module named `Lint` which provides several functions
 to lint a project/source file/source string.