Documentation correction for CASE_SENSE_NAMES

In issue #8129 the problem of using different case of filenames was addressed, though in the documentation it was not clear what this meant for input files.
This has been corrected (the underlying problem has been handled with different other commits a.o. 2b5a454 ).

Author: albert-github

src/config.xml

@@ -981,12 +981,17 @@ Go to the <a href="commands.html">next</a> section or return to the
     <option type='bool' id='CASE_SENSE_NAMES' defval='0' altdefval='Portable::fileSystemIsCaseSensitive()'>
       <docs>
 <![CDATA[
- If the \c CASE_SENSE_NAMES tag is set to \c NO then doxygen
- will only generate file names in lower-case letters. If set to
- \c YES, upper-case letters are also allowed. This is useful if you have
- classes or files whose names only differ in case and if your file system
- supports case sensitive file names. Windows (including Cygwin) and
- Mac users are advised to set this option to \c NO.
+ With \c CASE_SENSE_NAMES doxygen will be better able to match the
+ capabilities of the underlying file system.
+ In case the files system supports files whose name only differs in the
+ case used, the option must be set to \c YES to properly deal with such input files
+ if they appear in the input, whereas for file systems that are not case
+ sensitive the option should be be set to \c NO to properly deal with output files
+ for symbols that only differ in case, like two classes one named \c CLASS
+ and the other named \c Class and to support references to files without
+ having to specify the correct case.
+
+ On Windows (including Cygwin) and Mac users are advised to set this option to \c NO.
 ]]>
       </docs>
     </option>