patch 8.2.3525: option variable name does not match option name

Problem:    Option variable name does not match option name. (Christ van
            Willigen)
Solution:   Rename the variable.
diff --git a/src/structs.h b/src/structs.h
index 021206e..bd468a9 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -2864,7 +2864,7 @@
 #ifdef FEAT_COMPL_FUNC
     char_u	*b_p_cfu;	// 'completefunc'
     char_u	*b_p_ofu;	// 'omnifunc'
-    char_u	*b_p_thsfu;	// 'thesaurusfunc'
+    char_u	*b_p_tsrfu;	// 'thesaurusfunc'
 #endif
 #ifdef FEAT_EVAL
     char_u	*b_p_tfu;	// 'tagfunc'