Fix typos

Author: bwignall

Rakefile

@@ -73,7 +73,7 @@ end # task :post
 
 # Usage: rake page name="about.html"
 # You can also specify a sub-directory path.
-# If you don't specify a file extention we create an index.html at the path specified
+# If you don't specify a file extension we create an index.html at the path specified
 desc "Create a new page."
 task :page do
   name = ENV["name"] || "new-page.md"
@@ -101,7 +101,7 @@ task :preview do
   system "jekyll --auto --server"
 end # task :preview
 
-# Public: Alias - Maintains backwards compatability for theme switching.
+# Public: Alias - Maintains backwards compatibility for theme switching.
 task :switch_theme => "theme:switch"
 
 namespace :theme do

_posts/news/2014-11-19-announcing-scalajs-0.5.6.md

@@ -28,7 +28,7 @@ For changes introduced in 0.5.0, how to upgrade, getting started etc. have a loo
 
 In Scala.js 0.6.x, putting `@JSExport` on a class or an object will export it to its fully qualified name, rather than its simple name. To ease the transition to 0.6.x, Scala.js 0.5.6 will warn if an `@JSExport` annotation without explicit name is put on a top level object or class. Otherwise, such code would silently break when migrating to 0.6.x.
 
-To silence the warning, simply specify the desired name explicilty.
+To silence the warning, simply specify the desired name explicitly.
 
 #### @JSExportDescendentClasses
 

_posts/news/2021-01-12-announcing-scalajs-1.4.0.md

@@ -47,7 +47,7 @@ As a reminder, libraries compiled with 0.6.x cannot be used with Scala.js 1.x; t
 ### `java.lang.Class.isAssignableFrom`
 
 [`java.lang.Class.isAssignableFrom` had some serious issues](https://github.com/scala-js/scala-js/issues/4328), which we fixed in Scala.js 1.4.0.
-It now completly follows its specification on the JVM.
+It now completely follows its specification on the JVM.
 However, it is possible that some code was relying on the broken behavior, which was, in some cases, closer to how `isInstance` and `isInstanceOf` works on Scala.js.
 
 In particular, the following idiom, which we have seen before, is now broken more often than before:

_posts/news/2021-02-12-announcing-scalajs-1.5.0.md

@@ -88,7 +88,7 @@ Since they are SAM types, they can be created with anonymous functions, for exam
 val jsFun: js.Function1[Int, String] = arg => arg.toString()
 {% endhighlight %}
 
-The built-in JS function types can accomodate any function with a fixed number of parameters, up to 22.
+The built-in JS function types can accommodate any function with a fixed number of parameters, up to 22.
 However, they are not enough for more specialized use cases:
 
 * Function values with variadic arguments (varargs)

doc/planning.md

@@ -20,7 +20,7 @@ title: Planning
 - front page icons for Correctness, Speed and Interoperability
 - Documentation landing page, more content
 
-## Doc content/struture plan
+## Doc content/structure plan
 
 - Quick start