COMP: Inline static DESCRIPTION in itk-module.cmake

Replace the set(DOCUMENTATION "...") + DESCRIPTION "${DOCUMENTATION}"
indirection with a static one-liner literal.

itk_module() is a CMake macro, so ${ARGN} re-tokenizes its arguments
and list-splits any embedded ";". A future edit adding a semicolon or
"[" to the DOCUMENTATION string would silently produce spurious
"Unknown argument" AUTHOR_WARNINGs from CMake/ITKModuleMacros.cmake:111
on every configure (see PRs #6220, #6245).

The v4 ingestion pipeline (PR #6204) enforces this via
sanitize-history.py:patch_dynamic_description.

Author: hjmjohnson

Modules/Filtering/TextureFeatures/itk-module.cmake

@@ -1,10 +1,3 @@
-set(
-  DOCUMENTATION
-  "N-dimensional textural feature image filters: first-order,
-run-length, and co-occurrence (GLCM) features computed over a
-sliding window for radiomics and computer-vision pipelines."
-)
-
 itk_module(
   TextureFeatures
   DEPENDS
@@ -18,6 +11,7 @@ itk_module(
     ITKImageIntensity
     ITKImageNoise
     ITKGoogleTest
-  DESCRIPTION "${DOCUMENTATION}"
+  DESCRIPTION
+    "N-dimensional textural feature image filters: first-order, run-length, and co-occurrence (GLCM) features computed over a sliding window for radiomics and computer-vision pipelines."
   EXCLUDE_FROM_DEFAULT
 )