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/option.c b/src/option.c
index 385126e..7d86ccf 100644
--- a/src/option.c
+++ b/src/option.c
@@ -5433,7 +5433,7 @@
 #ifdef FEAT_COMPL_FUNC
 	case PV_CFU:	return (char_u *)&(curbuf->b_p_cfu);
 	case PV_OFU:	return (char_u *)&(curbuf->b_p_ofu);
-	case PV_THSFU:	return (char_u *)&(curbuf->b_p_thsfu);
+	case PV_THSFU:	return (char_u *)&(curbuf->b_p_tsrfu);
 #endif
 #ifdef FEAT_EVAL
 	case PV_TFU:	return (char_u *)&(curbuf->b_p_tfu);
@@ -5936,7 +5936,7 @@
 	    COPY_OPT_SCTX(buf, BV_CFU);
 	    buf->b_p_ofu = vim_strsave(p_ofu);
 	    COPY_OPT_SCTX(buf, BV_OFU);
-	    buf->b_p_thsfu = vim_strsave(p_thsfu);
+	    buf->b_p_tsrfu = vim_strsave(p_thsfu);
 	    COPY_OPT_SCTX(buf, BV_THSFU);
 #endif
 #ifdef FEAT_EVAL