patch 8.2.3315: cannot use single quote in a float number for readability

Problem:    Cannot use single quote in a float number for readability.
Solution:   Support single quotes like in numbers. (closes #8713)
diff --git a/src/json.c b/src/json.c
index 4b9a2e8..a8d3a09 100644
--- a/src/json.c
+++ b/src/json.c
@@ -791,12 +791,13 @@
 			    {
 				float_T f;
 
-				len = string2float(p, &f);
+				len = string2float(p, &f, FALSE);
 			    }
 			    else
 			    {
 				cur_item->v_type = VAR_FLOAT;
-				len = string2float(p, &cur_item->vval.v_float);
+				len = string2float(p, &cur_item->vval.v_float,
+									FALSE);
 			    }
 			}
 			else