feat(vim): add a couple of snippets for writing jest tests

site-modules/core/files/vim/snippets/snippets/js/before-each.snippet

@@ -0,0 +1,8 @@
+# name: Before each test function
+# key: be
+# contributor: Ade Attwood <code@adeattwood.co.uk>
+# filetypes: javascript,javascriptreact,typescript,typescriptreact
+# --
+beforeEach(${1:async }() => {
+  ${0}
+});

site-modules/core/files/vim/snippets/snippets/js/describe.snippet

@@ -0,0 +1,8 @@
+# name: Describe test function
+# key: desc
+# contributor: Ade Attwood <code@adeattwood.co.uk>
+# filetypes: javascript,javascriptreact,typescript,typescriptreact
+# --
+describe('${1}', () => {
+  ${0}
+});