InterpolatedStringWithNoSubstitution: updated docs

To reflect changes to the rule.

Author: webwarrior-ws

docs/content/how-tos/rules/FL0087.md

@@ -12,16 +12,18 @@ hide_menu: true
 
 Interpolated string (with `$` prefix, such as `$"foo"`) is used without embedded F# expression (e.g. `$"{foo}"` where foo is some value).
 
+Or string formatting function such as `sprintf` or `failwithf` is used without interpolation.
+
 ## Rationale
 
 Usage of interpolated string without embedded F# expression(s) may indicate that the expression was intended to be used but wasn't used by mistake.
 
-For regular strings, use regular string syntax.
-
 ## How To Fix
 
 Use regular string or embed F# expression using curly braces (`{}`).
 
+Use `failwith` instead of `failwithf` if no formatting/interpolation is needed.
+
 ## Rule Settings
 
     {

src/FSharpLint.Core/Text.resx

@@ -382,6 +382,6 @@
     <value>Prefer using the 'as' pattern to match a constant and bind it to a variable.</value>
   </data>
   <data name="InterpolatedStringWithNoSubstitution" xml:space="preserve">
-    <value>Use interpolated string (with $ prefix) only when embedding F# expression in that string using {}.</value>
+    <value>Do not use interpolated string syntax (with $ prefix) or formatting functions (sprintf, failwithf) when not really performing any interpolation.</value>
   </data>
 </root>