Help: Clarify status of link_libraries command

The command has been documented as 'deprecated', but it is not really
slated for removal and can still be used.  Clarify this in the
documentation.  While at it, revise the documentation to use wording
more consistent with that now in target_link_libraries.

Suggested-by: Christoph Grüninger <[email protected]>

Help/command/link_libraries.rst

@@ -1,16 +1,19 @@
 link_libraries
 --------------
 
-Deprecated. Use the target_link_libraries() command instead.
-
 Link libraries to all targets added later.
 
 ::
 
-  link_libraries(library1 <debug | optimized> library2 ...)
+  link_libraries([item1 [item2 [...]]]
+                 [[debug|optimized|general] <item>] ...)
+
+Specify libraries or flags to use when linking any targets created later in
+the current directory or below by commands such as :command:`add_executable`
+or :command:`add_library`.  See the :command:`target_link_libraries` command
+for meaning of arguments.
 
-Specify a list of libraries to be linked into any following targets
-(typically added with the add_executable or add_library calls).  This
-command is passed down to all subdirectories.  The debug and optimized
-strings may be used to indicate that the next library listed is to be
-used only for that specific type of build.
+.. note::
+  The :command:`target_link_libraries` command should be preferred whenever
+  possible.  Library dependencies are chained automatically, so directory-wide
+  specification of link libraries is rarely needed.

Help/manual/cmake-commands.7.rst

@@ -67,6 +67,7 @@ These commands may be used freely in CMake projects.
    /command/include
    /command/install
    /command/link_directories
+   /command/link_libraries
    /command/list
    /command/load_cache
    /command/load_command
@@ -117,7 +118,6 @@ versions of CMake.  Do not use them in new code.
    /command/install_files
    /command/install_programs
    /command/install_targets
-   /command/link_libraries
    /command/make_directory
    /command/output_required_files
    /command/remove