patch 9.0.0491: no good reason to build without the float feature

Problem:    No good reason to build without the float feature.
Solution:   Remove configure check for float and "#ifdef FEAT_FLOAT".
diff --git a/runtime/doc/mlang.txt b/runtime/doc/mlang.txt
index edab4d4..724ec46 100644
--- a/runtime/doc/mlang.txt
+++ b/runtime/doc/mlang.txt
@@ -82,9 +82,9 @@
 			characters. This sets $LC_COLLATE.
 			Without an argument all are set, and additionally
 			$LANG is set.
-			When compiled with the |+float| feature the LC_NUMERIC
-			value will always be set to "C", so that floating
-			point numbers use '.' as the decimal point.
+			If available the LC_NUMERIC value will always be set
+			to "C", so that floating point numbers use '.' as the
+			decimal point.
 			This will make a difference for items that depend on
 			the language (some messages, time and date format).
 			Not fully supported on all systems