patch 8.1.2371: FEAT_TEXT_PROP is a confusing name

Problem:    FEAT_TEXT_PROP is a confusing name.
Solution:   Use FEAT_PROP_POPUP. (Naruhiko Nishino, closes #5291)
diff --git a/src/option.h b/src/option.h
index 8319e0f..4ccf22a 100644
--- a/src/option.h
+++ b/src/option.h
@@ -567,7 +567,7 @@
 EXTERN int	p_fs;		// 'fsync'
 #endif
 EXTERN int	p_gd;		// 'gdefault'
-#ifdef FEAT_TEXT_PROP
+#ifdef FEAT_PROP_POPUP
 # ifdef FEAT_QUICKFIX
 EXTERN char_u	*p_cpp;		// 'completepopup'
 # endif