Help: Fix typos and style in add_link_options documentation

Help/command/LINK_OPTIONS_LINKER.txt

@@ -1,8 +1,8 @@
-To pass options to the linker tool, each compiler driver has is own syntax.
-The ``LINKER:`` prefix can be used to specify, in a portable way, options
-to pass to the linker tool. The ``LINKER:`` prefix is replaced by the required
-driver option and the rest of the option string defines linker arguments using
-``,`` as separator. These arguments will be formatted according to the
+To pass options to the linker tool, each compiler driver has its own syntax.
+The ``LINKER:`` prefix and ``,`` separator can be used to specify, in a portable
+way, options to pass to the linker tool. ``LINKER:`` is replaced by the
+appropriate driver option and ``,`` by the appropriate driver separator.
+The driver prefix and driver separator are given by the values of the
 :variable:`CMAKE_<LANG>_LINKER_WRAPPER_FLAG` and
 :variable:`CMAKE_<LANG>_LINKER_WRAPPER_FLAG_SEP` variables.
 
@@ -12,11 +12,11 @@ For example, ``"LINKER:-z,defs"`` becomes ``-Xlinker -z -Xlinker defs`` for
 The ``LINKER:`` prefix can be specified as part of a ``SHELL:`` prefix
 expression.
 
-The ``LINKER:`` prefix supports, as alternate syntax, specification of
-arguments using ``SHELL:`` prefix and space as separator. Previous example
-becomes ``"LINKER:SHELL:-z defs"``.
+The ``LINKER:`` prefix supports, as an alternative syntax, specification of
+arguments using the ``SHELL:`` prefix and space as separator. The previous
+example then becomes ``"LINKER:SHELL:-z defs"``.
 
 .. note::
 
-  Specifying ``SHELL:`` prefix elsewhere than at the beginning of the
+  Specifying the ``SHELL:`` prefix anywhere other than at the beginning of the
   ``LINKER:`` prefix is not supported.

Help/command/OPTIONS_SHELL.txt

@@ -1,9 +1,9 @@
 The final set of compile or link options used for a target is constructed by
 accumulating options from the current target and the usage requirements of
-it dependencies.  The set of options is de-duplicated to avoid repetition.
+its dependencies.  The set of options is de-duplicated to avoid repetition.
 While beneficial for individual options, the de-duplication step can break
 up option groups.  For example, ``-D A -D B`` becomes ``-D A B``.  One may
 specify a group of options using shell-like quoting along with a ``SHELL:``
-prefix.  The ``SHELL:`` prefix is dropped and the rest of the option string
+prefix.  The ``SHELL:`` prefix is dropped, and the rest of the option string
 is parsed using the :command:`separate_arguments` ``UNIX_COMMAND`` mode.
 For example, ``"SHELL:-D A" "SHELL:-D B"`` becomes ``-D A -D B``.