[backport] Fix spelling typos (#12755)

doc/manual.rst

@@ -1644,7 +1644,7 @@ object branch, the initialization is considered valid. This analysis only works
 for immutable discriminators of an ordinal type and disregards ``elif``
 branches. For discriminator values with a ``range`` type, the compiler
 checks if the entire range of possible values for the discriminator value is
-valid for the choosen object branch.
+valid for the chosen object branch.
 
 A small example:
 
@@ -3440,14 +3440,14 @@ different; for this a special setter syntax is needed:
     ## setter of hostAddr.
     ## This accesses the 'host' field and is not a recursive call to
     ## ``host=`` because the builtin dot access is preferred if it is
-    ## avaliable:
+    ## available:
     s.host = value
 
   proc host*(s: Socket): int {.inline.} =
     ## getter of hostAddr
     ## This accesses the 'host' field and is not a recursive call to
     ## ``host`` because the builtin dot access is preferred if it is
-    ## avaliable:
+    ## available:
     s.host
 
 .. code-block:: nim
@@ -5409,7 +5409,7 @@ expression by coercing it to a corresponding ``static`` type:
 
   echo static(fac(5)), " ", static[bool](16.isPowerOfTwo)
 
-The complier will report any failure to evaluate the expression or a
+The compiler will report any failure to evaluate the expression or a
 possible type mismatch error.
 
 typedesc[T]
@@ -5421,7 +5421,7 @@ all values must have a type, ``typedesc`` is considered their special type.
 
 ``typedesc`` acts like a generic type. For instance, the type of the symbol
 ``int`` is ``typedesc[int]``. Just like with regular generic types, when the
-generic param is ommited, ``typedesc`` denotes the type class of all types.
+generic param is omitted, ``typedesc`` denotes the type class of all types.
 As a syntactic convenience, you can also use ``typedesc`` as a modifier.
 
 Procs featuring ``typedesc`` params are considered implicitly generic.