Sync with "rush init --overwrite-existing --rush-example-repo" from R…

…ush 5.6.3

.gitattributes

@@ -3,3 +3,11 @@
 shrinkwrap.yaml              merge=binary
 npm-shrinkwrap.json          merge=binary
 yarn.lock                    merge=binary
+
+# Rush's JSON config files use JavaScript-style code comments.  The rule below prevents pedantic
+# syntax highlighters such as GitHub's from highlighting these comments as errors.  Your text editor
+# may also require a special configuration to allow comments in JSON.
+#
+# For more information, see this issue: https://github.com/Microsoft/web-build-tools/issues/1088
+#
+*.json            linguist-language=JSON5

rush.json

@@ -16,7 +16,7 @@
    * path segment in the "$schema" field for all your Rush config files.  This will ensure
    * correct error-underlining and tab-completion for editors such as VS Code.
    */
-  "rushVersion": "5.6.1",
+  "rushVersion": "5.6.3",
 
   /**
    * The next field selects which package manager should be installed and determines its version.