Mark print and println as inline

Allows the string call to specialize for certain types and avoid
unnecessary .ToString() calls.

Author: bbatsov

src/FSharp.Core/fslib-extra-pervasives.fs

@@ -278,11 +278,11 @@ module ExtraTopLevelOperators =
         Printf.eprintfn format
 
     [<CompiledName("PrintValue")>]
-    let print (value: 'T) =
+    let inline print (value: 'T) =
         Console.Out.Write(string value)
 
     [<CompiledName("PrintValueLine")>]
-    let println (value: 'T) =
+    let inline println (value: 'T) =
         Console.Out.WriteLine(string value)
 
     [<CompiledName("DefaultAsyncBuilder")>]

src/FSharp.Core/fslib-extra-pervasives.fsi

@@ -68,7 +68,7 @@ module ExtraTopLevelOperators =
     /// </code>
     /// </example>
     [<CompiledName("PrintValue")>]
-    val print: value: 'T -> unit
+    val inline print: value: 'T -> unit
 
     /// <summary>Converts the value to a string using the <c>string</c> operator and writes it to the standard output, followed by a newline.</summary>
     ///
@@ -81,7 +81,7 @@ module ExtraTopLevelOperators =
     /// </code>
     /// </example>
     [<CompiledName("PrintValueLine")>]
-    val println: value: 'T -> unit
+    val inline println: value: 'T -> unit
 
     /// <summary>Print to a string using the given format.</summary>
     ///