[format minor] remove unnecessary spaces (nim-lang#19216)

lib/system/atomics.nim

@@ -73,7 +73,7 @@ when someGcc and hasThreadSupport:
 
   proc atomicCompareExchangeN*[T: AtomType](p, expected: ptr T, desired: T,
     weak: bool, success_memmodel: AtomMemModel, failure_memmodel: AtomMemModel): bool {.
-    importc: "__atomic_compare_exchange_n ", nodecl.}
+    importc: "__atomic_compare_exchange_n", nodecl.}
     ## This proc implements an atomic compare and exchange operation. This compares the
     ## contents at p with the contents at expected and if equal, writes desired at p.
     ## If they are not equal, the current contents at p is written into expected.
@@ -100,13 +100,13 @@ when someGcc and hasThreadSupport:
   proc atomicSubFetch*[T: AtomType](p: ptr T, val: T, mem: AtomMemModel): T {.
     importc: "__atomic_sub_fetch", nodecl.}
   proc atomicOrFetch*[T: AtomType](p: ptr T, val: T, mem: AtomMemModel): T {.
-    importc: "__atomic_or_fetch ", nodecl.}
+    importc: "__atomic_or_fetch", nodecl.}
   proc atomicAndFetch*[T: AtomType](p: ptr T, val: T, mem: AtomMemModel): T {.
     importc: "__atomic_and_fetch", nodecl.}
   proc atomicXorFetch*[T: AtomType](p: ptr T, val: T, mem: AtomMemModel): T {.
     importc: "__atomic_xor_fetch", nodecl.}
   proc atomicNandFetch*[T: AtomType](p: ptr T, val: T, mem: AtomMemModel): T {.
-    importc: "__atomic_nand_fetch ", nodecl.}
+    importc: "__atomic_nand_fetch", nodecl.}
 
   ## Perform the operation return the old value, all memory models are valid
   proc atomicFetchAdd*[T: AtomType](p: ptr T, val: T, mem: AtomMemModel): T {.
@@ -177,8 +177,8 @@ elif someVcc and hasThreadSupport:
 
   proc `==`(x1, x2: AtomMemModel): bool {.borrow.}
 
-  proc readBarrier() {.importc: "_ReadBarrier",  header: "<intrin.h>".}
-  proc writeBarrier() {.importc: "_WriteBarrier",  header: "<intrin.h>".}
+  proc readBarrier() {.importc: "_ReadBarrier", header: "<intrin.h>".}
+  proc writeBarrier() {.importc: "_WriteBarrier", header: "<intrin.h>".}
   proc fence*() {.importc: "_ReadWriteBarrier", header: "<intrin.h>".}
 
   template barrier(mem: AtomMemModel) =