doc: a typo fix

Author: jyno12

README.md

@@ -14,7 +14,7 @@ import "golang.design/x/mainthread"
 ## API Usage
 
 Package mainthread offers facilities to schedule functions on the
-maint hread. To use this package properly, one must call
+main thread. To use this package properly, one must call
 mainthread.Init from the main package. For example:
 
 ```go

mainthread.go

@@ -5,7 +5,7 @@
 // Written by Changkun Ou <changkun.de>
 
 // Package mainthread offers facilities to schedule functions on the
-// maint hread. To use this package properly, one must call
+// main thread. To use this package properly, one must call
 // mainthread.Init from the main package. For example:
 //
 // 	package main