Silence several Hint[Performance] warnings (#23003)

With `--mm:arc` one gets the "implicit copy; if possible, rearrange your
program's control flow" `Performance` warnings without these `move`s.

lib/pure/httpclient.nim

@@ -1232,7 +1232,7 @@ proc responseContent(resp: Response | AsyncResponse): Future[string] {.multisync
   ## A `HttpRequestError` will be raised if the server responds with a
   ## client error (status code 4xx) or a server error (status code 5xx).
   if resp.code.is4xx or resp.code.is5xx:
-    raise newException(HttpRequestError, resp.status)
+    raise newException(HttpRequestError, resp.status.move)
   else:
     return await resp.bodyStream.readAll()
 

lib/pure/httpcore.nim

@@ -234,10 +234,9 @@ func parseList(line: string, list: var seq[string], start: int): int =
   while start+i < line.len and line[start + i] notin {'\c', '\l'}:
     i += line.skipWhitespace(start + i)
     i += line.parseUntil(current, {'\c', '\l', ','}, start + i)
-    list.add(current)
+    list.add(move current)  # implicit current.setLen(0)
     if start+i < line.len and line[start + i] == ',':
       i.inc # Skip ,
-    current.setLen(0)
 
 func parseHeader*(line: string): tuple[key: string, value: seq[string]] =
   ## Parses a single raw header HTTP line into key value pairs.

lib/pure/parsecfg.nim

@@ -452,7 +452,7 @@ proc getKeyValPair(c: var CfgParser, kind: CfgEventKind): CfgEvent =
   if c.tok.kind == tkSymbol:
     case kind
     of cfgOption, cfgKeyValuePair:
-      result = CfgEvent(kind: kind, key: c.tok.literal, value: "")
+      result = CfgEvent(kind: kind, key: c.tok.literal.move, value: "")
     else: discard
     rawGetTok(c, c.tok)
     if c.tok.kind in {tkEquals, tkColon}:
@@ -481,7 +481,7 @@ proc next*(c: var CfgParser): CfgEvent {.rtl, extern: "npc$1".} =
   of tkBracketLe:
     rawGetTok(c, c.tok)
     if c.tok.kind == tkSymbol:
-      result = CfgEvent(kind: cfgSectionStart, section: c.tok.literal)
+      result = CfgEvent(kind: cfgSectionStart, section: c.tok.literal.move)
     else:
       result = CfgEvent(kind: cfgError,
         msg: errorStr(c, "symbol expected, but found: " & c.tok.literal))

lib/std/cmdline.nim

@@ -138,7 +138,7 @@ proc parseCmdLine*(c: string): seq[string] {.
         while i < c.len and c[i] > ' ':
           add(a, c[i])
           inc(i)
-    add(result, a)
+    add(result, move a)
 
 when defined(nimdoc):
   # Common forward declaration docstring block for parameter retrieval procs.