feat: implement std.round (#1064)

Co-authored-by: Dave Cunningham <[email protected]>

Author: rohitjangid

doc/_stdlib_gen/stdlib-content.jsonnet

@@ -183,6 +183,7 @@ local html = import 'html.libsonnet';
               <ul><code>std.asin(x)</code></ul>
               <ul><code>std.acos(x)</code></ul>
               <ul><code>std.atan(x)</code></ul>
+              <ul><code>std.round(x)</code></ul>
           </ul>
           <p>
               The function <code>std.mod(a, b)</code> is what the % operator is desugared to. It performs

stdlib/std.jsonnet

@@ -1707,5 +1707,7 @@ limitations under the License.
 
   xnor(x, y):: x == y,
 
+  round(x):: std.floor(x + 0.5),
+
   isEmpty(str):: std.length(str) == 0,
 }

test_suite/stdlib.jsonnet

@@ -1550,6 +1550,9 @@ std.assertEqual(std.xor(true, true), false) &&
 std.assertEqual(std.xnor(true, false), false) &&
 std.assertEqual(std.xnor(true, true), true) &&
 
+std.assertEqual(std.round(1.2), 1) &&
+std.assertEqual(std.round(1.5), 2) &&
+
 std.assertEqual(std.isEmpty(''), true) &&
 std.assertEqual(std.isEmpty('non-empty string'), false) &&