Add heuristic for JSX with more than one child.

Fixes #18

Variadic JSX such as `<C> {x} {y} </C>` triggers the definition of 4 values at the same location. Only one of them is the desired one for hover and jump to definition.

Author: cristianoc

examples/example-project/src/ZZ.res

@@ -1,18 +1,21 @@
-
-
 let a = 12
 
 let b = [1, 2, 3, a]
 
-
 let c = <div />
 
 let s = React.string
 
-// module M = {
-//   @react.component
-//   let make = (~x) => React.string(x)
-// }
+module M = {
+  @react.component
+  let make = (~x) => React.string(x)
+}
+
+let d = <M x="abc" />
 
+module J = {
+  @react.component
+  export make = (~children: React.element) => React.null
+}
 
-// let d = <M x="abc" />
+let z = <J> {React.string("")} {React.string("")} </J>

src/rescript-editor-support/References.re

@@ -31,7 +31,13 @@ let locForPos = (~extra, pos) => {
   switch (locsForPos(~extra, pos)) {
   | [(loc1, _), (loc2, _) as l, (loc3, _)]
       when loc1 == loc2 && loc2 == loc3 =>
-    // heuristic for: [makeProps, make, createElements], give the loc of `make`
+    // JSX with at most one child
+    // heuristic for: [makeProps, make, createElement], give the loc of `make`
+    Some(l)
+  | [(loc1, _), (loc2, _), (loc3, _) as l, (loc4, _)]
+      when loc1 == loc2 && loc2 == loc3 && loc3 == loc4 =>
+    // JSX variadic, e.g. <C> {x} {y} </C>
+    // heuristic for: [makeProps, React.null, make, createElementVariadic], give the loc of `make`
     Some(l)
   | [l, ..._] => Some(l)
   | _ => None