Clean out strutils (#14859)

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

changelog.md

@@ -186,6 +186,7 @@ proc mydiv(a, b): int {.raises: [].} =
 
 - Added the `thiscall` calling convention as specified by Microsoft, mostly for hooking purpose
 - Deprecated `{.unroll.}` pragma, was ignored by the compiler anyways, was a nop.
+- Remove `strutils.isNilOrWhitespace`, was deprecated.
 - Remove `sharedtables.initSharedTable`, was deprecated and produces undefined behavior.
 - Removed `asyncdispatch.newAsyncNativeSocket`, was deprecated since `0.18`.
 - Remove `dom.releaseEvents` and `dom.captureEvents`, was deprecated.

lib/pure/strutils.nim

@@ -2935,11 +2935,6 @@ proc isEmptyOrWhitespace*(s: string): bool {.noSideEffect, rtl,
   ## Checks if `s` is empty or consists entirely of whitespace characters.
   result = s.allCharsInSet(Whitespace)
 
-proc isNilOrWhitespace*(s: string): bool {.noSideEffect, rtl,
-    extern: "nsuIsNilOrWhitespace",
-    deprecated: "use isEmptyOrWhitespace instead".} =
-  ## Alias for isEmptyOrWhitespace
-  result = isEmptyOrWhitespace(s)
 
 when isMainModule:
   proc nonStaticTests =