Improve strutils.rsplit doc, proc and iterator have oppose result ord…

…er. (#23570)

[`rsplit
iterator`](https://nim-lang.org/docs/strutils.html#rsplit.i,string,char,int)
yields substring in reversed order,

while [`proc
rsplit`](https://nim-lang.org/docs/strutils.html#rsplit%2Cstring%2Cchar%2Cint)'s
order is not reversed, but its doc only declare ```
The same as the rsplit iterator, but is a func that returns a sequence
of substrings.
```

lib/pure/strutils.nim

@@ -565,7 +565,7 @@ iterator rsplit*(s: string, sep: char,
                  maxsplit: int = -1): string =
   ## Splits the string `s` into substrings from the right using a
   ## string separator. Works exactly the same as `split iterator
-  ## <#split.i,string,char,int>`_ except in reverse order.
+  ## <#split.i,string,char,int>`_ except in **reverse** order.
   ##
   ##   ```nim
   ##   for piece in "foo:bar".rsplit(':'):
@@ -592,7 +592,7 @@ iterator rsplit*(s: string, seps: set[char] = Whitespace,
                  maxsplit: int = -1): string =
   ## Splits the string `s` into substrings from the right using a
   ## string separator. Works exactly the same as `split iterator
-  ## <#split.i,string,char,int>`_ except in reverse order.
+  ## <#split.i,string,char,int>`_ except in **reverse** order.
   ##
   ##   ```nim
   ##   for piece in "foo bar".rsplit(WhiteSpace):
@@ -622,7 +622,7 @@ iterator rsplit*(s: string, sep: string, maxsplit: int = -1,
                  keepSeparators: bool = false): string =
   ## Splits the string `s` into substrings from the right using a
   ## string separator. Works exactly the same as `split iterator
-  ## <#split.i,string,string,int>`_ except in reverse order.
+  ## <#split.i,string,string,int>`_ except in **reverse** order.
   ##
   ##   ```nim
   ##   for piece in "foothebar".rsplit("the"):
@@ -805,7 +805,7 @@ func split*(s: string, sep: string, maxsplit: int = -1): seq[string] {.rtl,
 func rsplit*(s: string, sep: char, maxsplit: int = -1): seq[string] {.rtl,
     extern: "nsuRSplitChar".} =
   ## The same as the `rsplit iterator <#rsplit.i,string,char,int>`_, but is a func
-  ## that returns a sequence of substrings.
+  ## that returns a sequence of substrings in original order.
   ##
   ## A possible common use case for `rsplit` is path manipulation,
   ## particularly on systems that don't use a common delimiter.
@@ -835,7 +835,7 @@ func rsplit*(s: string, seps: set[char] = Whitespace,
              maxsplit: int = -1): seq[string]
              {.rtl, extern: "nsuRSplitCharSet".} =
   ## The same as the `rsplit iterator <#rsplit.i,string,set[char],int>`_, but is a
-  ## func that returns a sequence of substrings.
+  ## func that returns a sequence of substrings in original order.
   ##
   ## A possible common use case for `rsplit` is path manipulation,
   ## particularly on systems that don't use a common delimiter.
@@ -867,7 +867,7 @@ func rsplit*(s: string, seps: set[char] = Whitespace,
 func rsplit*(s: string, sep: string, maxsplit: int = -1): seq[string] {.rtl,
     extern: "nsuRSplitString".} =
   ## The same as the `rsplit iterator <#rsplit.i,string,string,int,bool>`_, but is a func
-  ## that returns a sequence of substrings.
+  ## that returns a sequence of substrings in original order.
   ##
   ## A possible common use case for `rsplit` is path manipulation,
   ## particularly on systems that don't use a common delimiter.