diff --git a/lib/pure/unicode.nim b/lib/pure/unicode.nim
index 0d5b06c92c..f90fc2745d 100644
--- a/lib/pure/unicode.nim
+++ b/lib/pure/unicode.nim
@@ -132,7 +132,9 @@ proc toUTF8*(c: TRune): string {.rtl, extern: "nuc$1".} =
     result = newString(1)
     result[0] = chr(i)
 
-proc `$`*(rune: TRune): string = rune.toUTF8
+proc `$`*(rune: TRune): string =
+  ## converts a rune to a string
+  rune.toUTF8
 
 proc `$`*(runes: seq[TRune]): string =
   ## converts a sequence of runes to a string