Add simpler content on promises

RoyalIcing · RoyalIcing · commit f51eaaad3392 · 2020-10-01T21:20:02.000+10:00
diff --git a/apps/components_guide_web/lib/components_guide_web/templates/web/promise.html.md b/apps/components_guide_web/lib/components_guide_web/templates/web/promise.html.md
@@ -1 +1,3 @@
 # Promise
+
+You can think of a Promise as a value. Once a Promise has been created, you can’t changed the value. Sooner or later its value will be given — as promised. Or it may fail with an error.

Original file line number	Diff line number	Diff line change
`@@ -1 +1,3 @@`
`1`	`1`	`# Promise`
	`2`	`+`
	`3`	`+You can think of a Promise as a value. Once a Promise has been created, you can’t changed the value. Sooner or later its value will be given — as promised. Or it may fail with an error.`