Copy editing (#15733)

* Minor fixes

* Minor fixes

* Minor fixes

* Minor fixes

doc/gc.rst

@@ -26,8 +26,8 @@ To choose the memory management strategy use the ``--gc:`` switch.
 
 - ``--gc:refc``. This is the default GC. It's a
   deferred reference counting based garbage collector
-  with a simple Mark&Sweep backup GC in order to collect cycles. Heaps are thread local.
-- ``--gc:markAndSweep``. Simple Mark-And-Sweep based garbage collector. Heaps are thread local.
+  with a simple Mark&Sweep backup GC in order to collect cycles. Heaps are thread-local.
+- ``--gc:markAndSweep``. Simple Mark-And-Sweep based garbage collector. Heaps are thread-local.
 - ``--gc:boehm``. Boehm based garbage collector, it offers a shared heap.
 - ``--gc:go``. Go's garbage collector, useful for interoperability with Go. Offers a shared heap.
 - ``--gc:arc``. Plain reference counting with
@@ -36,10 +36,10 @@ To choose the memory management strategy use the ``--gc:`` switch.
   cause memory leaks, beware.
 
 - ``--gc:orc``. Same as ``--gc:arc`` but adds a cycle collector based on "trial deletion".
-  Unfortunately that makes its performance profile hard to reason about so it is less
-  useful for hard realtime systems.
+  Unfortunately, that makes its performance profile hard to reason about so it is less
+  useful for hard real-time systems.
 
-- ``--gc:none``. No memory management strategy nor garbage collector. Allocated memory is
+- ``--gc:none``. No memory management strategy nor a garbage collector. Allocated memory is
   simply never freed. You should use ``--gc:arc`` instead.
 
 
@@ -71,10 +71,10 @@ The cycle collector can be en-/disabled independently from the other parts of
 the garbage collector with ``GC_enableMarkAndSweep`` and ``GC_disableMarkAndSweep``.
 
 
-Soft realtime support
+Soft real-time support
 ---------------------
 
-To enable realtime support, the symbol `useRealtimeGC`:idx: needs to be
+To enable real-time support, the symbol `useRealtimeGC`:idx: needs to be
 defined via ``--define:useRealtimeGC`` (you can put this into your config
 file as well).
 With this switch the garbage collector supports the following operations:
@@ -85,7 +85,7 @@ With this switch the garbage collector supports the following operations:
 
 The unit of the parameters ``maxPauseInUs`` and ``us`` is microseconds.
 
-These two procs are the two modus operandi of the realtime garbage collector:
+These two procs are the two modus operandi of the real-time garbage collector:
 
 (1) GC_SetMaxPause Mode
 
@@ -98,7 +98,7 @@ These two procs are the two modus operandi of the realtime garbage collector:
 (2) GC_step Mode
 
     This allows the garbage collector to perform some work for up to ``us`` time.
-    This is useful to call in a main loop to ensure the garbage collector can do its work.
+    This is useful to call in the main loop to ensure the garbage collector can do its work.
     To bind all garbage collector activity to a ``GC_step`` call,
     deactivate the garbage collector with ``GC_disable`` at program startup.
     If ``strongAdvice`` is set to ``true``,
@@ -106,13 +106,13 @@ These two procs are the two modus operandi of the realtime garbage collector:
     Otherwise, the garbage collector may decide not to do anything,
     if there is not much garbage to collect.
     You may also specify the current stack size via ``stackSize`` parameter.
-    It can improve performance, when you know that there are no unique Nim
-    references below certain point on the stack. Make sure the size you specify
-    is greater than the potential worst case size.
+    It can improve performance when you know that there are no unique Nim
+    references below a certain point on the stack. Make sure the size you specify
+    is greater than the potential worst-case size.
 
-These procs provide a "best effort" realtime guarantee; in particular the
+These procs provide a "best effort" real-time guarantee; in particular the
 cycle collector is not aware of deadlines. Deactivate it to get more
-predictable realtime behaviour. Tests show that a 1ms max pause
+predictable real-time behaviour. Tests show that a 1ms max pause
 time will be met in almost all cases on modern CPUs (with the cycle collector
 disabled).
 
@@ -120,14 +120,14 @@ disabled).
 Time measurement with garbage collectors
 ----------------------------------------
 
-The garbage collectors's way of measuring time uses
+The garbage collectors' way of measuring time uses
 (see ``lib/system/timers.nim`` for the implementation):
 
 1) ``QueryPerformanceCounter`` and ``QueryPerformanceFrequency`` on Windows.
 2) ``mach_absolute_time`` on Mac OS X.
 3) ``gettimeofday`` on Posix systems.
 
-As such it supports a resolution of nanoseconds internally; however the API
+As such it supports a resolution of nanoseconds internally; however, the API
 uses microseconds for convenience.
 
 Define the symbol ``reportMissedDeadlines`` to make the