PPHA-263: Use correct weight label wording

Author: Themitchell

lung_cancer_screening/questions/jinja2/weight.jinja

@@ -37,7 +37,7 @@
 
         {% call fieldset({
           "legend": {
-            "text": "What is your weight",
+            "text": "How much do you weigh?",
             "classes": "nhsuk-label--m"
           }
         }) %}