clean up gc:arc or gc:orc in docs and in error messages (#22408)

* clean up gc:arc/orc in docs

* in error messages

compiler/ccgexprs.nim

@@ -2621,7 +2621,7 @@ proc genMagicExpr(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
   of mDeepCopy:
     if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc} and optEnableDeepCopy notin p.config.globalOptions:
       localError(p.config, e.info,
-        "for --gc:arc|orc 'deepcopy' support has to be enabled with --deepcopy:on")
+        "for --mm:arc|atomicArc|orc 'deepcopy' support has to be enabled with --deepcopy:on")
 
     var a, b: TLoc = default(TLoc)
     let x = if e[1].kind in {nkAddr, nkHiddenAddr}: e[1][0] else: e[1]

lib/std/tasks.nim

@@ -111,7 +111,7 @@ template addAllNode(assignParam: NimNode, procParam: NimNode) =
 
 macro toTask*(e: typed{nkCall | nkInfix | nkPrefix | nkPostfix | nkCommand | nkCallStrLit}): Task =
   ## Converts the call and its arguments to `Task`.
-  runnableExamples("--gc:orc"):
+  runnableExamples:
     proc hello(a: int) = echo a
 
     let b = toTask hello(13)
@@ -259,7 +259,7 @@ macro toTask*(e: typed{nkCall | nkInfix | nkPrefix | nkPostfix | nkCommand | nkC
   when defined(nimTasksDebug):
     echo result.repr
 
-runnableExamples("--gc:orc"):
+runnableExamples:
   block:
     var num = 0
     proc hello(a: int) = inc num, a

lib/system.nim

@@ -2565,7 +2565,7 @@ when hasAlloc and notJSnotNims:
     ## This is also used by the code generator
     ## for the implementation of `spawn`.
     ##
-    ## For `--gc:arc` or `--gc:orc` deepcopy support has to be enabled
+    ## For `--mm:arc` or `--mm:orc` deepcopy support has to be enabled
     ## via `--deepcopy:on`.
     discard
 
@@ -2811,7 +2811,7 @@ when notJSnotNims and not defined(nimSeqsV2):
     ## String literals (e.g. "abc", etc) in the ARC/ORC mode are "copy on write",
     ## therefore you should call `prepareMutation` before modifying the strings
     ## via `addr`.
-    runnableExamples("--gc:arc"):
+    runnableExamples:
       var x = "abc"
       var y = "defgh"
       prepareMutation(y) # without this, you may get a `SIGBUS` or `SIGSEGV`

lib/system/arc.nim

@@ -223,15 +223,15 @@ proc GC_ref*[T](x: ref T) =
 
 when not defined(gcOrc):
   template GC_fullCollect* =
-    ## Forces a full garbage collection pass. With `--gc:arc` a nop.
+    ## Forces a full garbage collection pass. With `--mm:arc` a nop.
     discard
 
 template setupForeignThreadGc* =
-  ## With `--gc:arc` a nop.
+  ## With `--mm:arc` a nop.
   discard
 
 template tearDownForeignThreadGc* =
-  ## With `--gc:arc` a nop.
+  ## With `--mm:arc` a nop.
   discard
 
 proc isObjDisplayCheck(source: PNimTypeV2, targetDepth: int16, token: uint32): bool {.compilerRtl, inl.} =

lib/system/orc.nim

@@ -424,13 +424,13 @@ proc GC_runOrc* =
   orcAssert roots.len == 0, "roots not empty!"
 
 proc GC_enableOrc*() =
-  ## Enables the cycle collector subsystem of `--gc:orc`. This is a `--gc:orc`
+  ## Enables the cycle collector subsystem of `--mm:orc`. This is a `--mm:orc`
   ## specific API. Check with `when defined(gcOrc)` for its existence.
   when not defined(nimStressOrc):
     rootsThreshold = 0
 
 proc GC_disableOrc*() =
-  ## Disables the cycle collector subsystem of `--gc:orc`. This is a `--gc:orc`
+  ## Disables the cycle collector subsystem of `--mm:orc`. This is a `--mm:orc`
   ## specific API. Check with `when defined(gcOrc)` for its existence.
   when not defined(nimStressOrc):
     rootsThreshold = high(int)
@@ -441,16 +441,16 @@ proc GC_partialCollect*(limit: int) =
   partialCollect(limit)
 
 proc GC_fullCollect* =
-  ## Forces a full garbage collection pass. With `--gc:orc` triggers the cycle
+  ## Forces a full garbage collection pass. With `--mm:orc` triggers the cycle
   ## collector. This is an alias for `GC_runOrc`.
   collectCycles()
 
 proc GC_enableMarkAndSweep*() =
-  ## For `--gc:orc` an alias for `GC_enableOrc`.
+  ## For `--mm:orc` an alias for `GC_enableOrc`.
   GC_enableOrc()
 
 proc GC_disableMarkAndSweep*() =
-  ## For `--gc:orc` an alias for `GC_disableOrc`.
+  ## For `--mm:orc` an alias for `GC_disableOrc`.
   GC_disableOrc()
 
 const

lib/system/osalloc.nim

@@ -30,7 +30,7 @@ const doNotUnmap = not (defined(amd64) or defined(i386)) or
 
 when defined(nimAllocPagesViaMalloc):
   when not defined(gcArc) and not defined(gcOrc) and not defined(gcAtomicArc):
-    {.error: "-d:nimAllocPagesViaMalloc is only supported with --gc:arc or --gc:orc".}
+    {.error: "-d:nimAllocPagesViaMalloc is only supported with --mm:arc or --mm:atomicArc or --mm:orc".}
 
   proc osTryAllocPages(size: int): pointer {.inline.} =
     let base = c_malloc(csize_t size + PageSize - 1 + sizeof(uint32))