DOC: Corrected setting for CASE_SENSE_NAMES

The default setting for `CASE_SENSE_NAMES` (in doxygen) is `SYSTEM` which means that on Linux it is set to `YES` and on (e.g.) Windows to `NO` (see analysis in InsightSoftwareConsortium#5262 (comment)).
Seen the usage of the `EXCLUDE_PATTERN` `*/test*` this meant on Windows that also the directory with the name `TestKernel` was matched and thus excluded.
Setting the `CASE_SENSE_NAMES` explicitly to `YES` prevents this (on Linux it won't have any effect as here the default was sufficient).
Note: Due to a bug in doxygen (see doxygen/doxygen#11519) this would still exclude the pattern. The new setting will only have an effect, on Windows, when, the not yet released, doxygen 1.14.0 or newer will be used.

Author: albert-github

Utilities/Doxygen/DoxygenConfig.cmake

@@ -24,6 +24,7 @@ set(DOXYGEN_TOC_INCLUDE_HEADINGS "0")
 set(DOXYGEN_BUILTIN_STL_SUPPORT "YES")
 set(DOXYGEN_DISTRIBUTE_GROUP_DOC "YES")
 set(DOXYGEN_LOOKUP_CACHE_SIZE "2")
+set(DOXYGEN_CASE_SENSE_NAMES "YES")
 set(DOXYGEN_EXTRACT_ALL "YES")
 set(DOXYGEN_EXTRACT_PRIVATE "YES")
 set(DOXYGEN_EXTRACT_STATIC "YES")