Help: Improve Cache documentation

Help/prop_cache/ADVANCED.rst

@@ -4,5 +4,5 @@ ADVANCED
 True if entry should be hidden by default in GUIs.
 
 This is a boolean value indicating whether the entry is considered
-interesting only for advanced configuration.  The mark_as_advanced()
+interesting only for advanced configuration.  The :command:`mark_as_advanced`
 command modifies this property.

Help/prop_cache/STRINGS.rst

@@ -1,9 +1,9 @@
 STRINGS
 -------
 
-Enumerate possible STRING entry values for GUI selection.
+Enumerate possible ``STRING`` entry values for GUI selection.
 
-For cache entries with type STRING, this enumerates a set of values.
+For cache entries with type ``STRING``, this enumerates a set of values.
 CMake GUIs may use this to provide a selection widget instead of a
 generic string entry field.  This is for convenience only.  CMake does
 not enforce that the value matches one of those listed.

Help/prop_cache/TYPE.rst

@@ -5,7 +5,7 @@ Widget type for entry in GUIs.
 
 Cache entry values are always strings, but CMake GUIs present widgets
 to help users set values.  The GUIs use this property as a hint to
-determine the widget type.  Valid TYPE values are:
+determine the widget type.  Valid ``TYPE`` values are:
 
 ::
 
@@ -17,5 +17,5 @@ determine the widget type.  Valid TYPE values are:
   STATIC        = Value managed by CMake, do not change.
   UNINITIALIZED = Type not yet specified.
 
-Generally the TYPE of a cache entry should be set by the command which
-creates it (set, option, find_library, etc.).
+Generally the ``TYPE`` of a cache entry should be set by the command which
+creates it ( :command:`set`, :command:`option`, :command:`find_library`, etc.).