Improve spelling of parameter names in documentation

root/documentation/ld.conf

@@ -22,13 +22,13 @@
       </id>
       <d_prime>
         type=Float
-        description=Measure of LD. If d_prime is provided only return pairs of variants whose d_prime value is equal to or greater than the value provided. 
+        description=Measure of LD. If D' is provided only return pairs of variants whose D' value is equal to or greater than the value provided. 
         default=0
         example=__VAR(d_prime)__
       </d_prime> 
       <r2>
         type=Float
-        description=Measure of LD. If r2 is provided only return pairs of variants whose r2 value is equal to or greater than the value provided. 
+        description=Measure of LD. If r-squared is provided only return pairs of variants whose r-square value is equal to or greater than the value provided. 
         default=0
         example=__VAR(r2)__
       </r2>