[WP][FIX][DOC] (libstfinv): provide unqiue section label

src/libs/libstfinv/doxygen_end_users.txt

@@ -39,6 +39,7 @@
   - \ref page_eu_subsec_introduction
   - \ref page_eu_subsec_parameters
 - \ref page_eu_sec_texts
+  - \ref page_eu_subsec_texts_lib 
   - \ref page_eu_subsec_texts_any 
   - \ref page_eu_subsec_texts_base 
   - \ref page_eu_subsec_texts_fourier 
@@ -115,7 +116,7 @@
 
 \section page_eu_sec_texts End-user usage information text files
 
-\subsection page_eu_subsec_texts_any Summary and detailed description for overall library
+\subsection page_eu_subsec_texts_lib Summary and detailed description for overall library
 \verbinclude ./stfinv_summary_usage.txt
 \verbinclude ./stfinv_description_usage.txt