fix: backwater curve: rename water ligne to ZW, add water depth as Y

refs #333

src/open-channel/remous.ts

@@ -445,9 +445,10 @@ export class CourbeRemous extends SectionNub {
             } else {
                 ligneDeau = Math.max(crbFlu[x], crbTor[x]);
             }
-            const re = new ResultElement({ Y: ligneDeau + this.getCoteFond(x) });
+            const re = new ResultElement({ ZW: ligneDeau + this.getCoteFond(x) });
 
             re.addExtraResult("X", x);
+            re.addExtraResult("Y", ligneDeau);
 
             if (crbFlu[x]) {
                 re.addExtraResult("flu", crbFlu[x] + this.getCoteFond(x));