Add CHANGELOG + improvements to #980

Closes #978

docs/docs/usage.md

@@ -442,8 +442,13 @@ tasks:
 ## Platform specific tasks and commands
 
 If you want to restrict the running of tasks to explicit platforms, this can be achieved
-using the `platforms` key. Tasks can be restricted to a specific OS, architecture or a
+using the `platforms:` key. Tasks can be restricted to a specific OS, architecture or a
 combination of both.
+On a mismatch, the task or command will be skipped, and no error will be thrown.
+
+The values allowed as OS or Arch are valid `GOOS` and `GOARCH` values, as
+defined by the Go language
+[here](https://github.com/golang/go/blob/master/src/go/build/syslist.go).
 
 The `build-windows` task below will run only on Windows, and on any architecture:
 
@@ -454,7 +459,7 @@ tasks:
   build-windows:
     platforms: [windows]
     cmds:
-      - echo 'Running command on windows'
+      - echo 'Running command on Windows'
 ```
 
 This can be restricted to a specific architecture as follows:
@@ -466,7 +471,7 @@ tasks:
   build-windows-amd64:
     platforms: [windows/amd64]
     cmds:
-      - echo 'Running command on windows (amd64)'
+      - echo 'Running command on Windows (amd64)'
 ```
 
 It is also possible to restrict the task to specific architectures:
@@ -487,10 +492,10 @@ Multiple platforms can be specified as follows:
 version: '3'
 
 tasks:
-  build-windows:
+  build:
     platforms: [windows/amd64, darwin]
     cmds:
-      - echo 'Running command on windows (amd64) and darwin'
+      - echo 'Running command on Windows (amd64) and macOS'
 ```
 
 Individual commands can also be restricted to specific platforms:
@@ -499,9 +504,9 @@ Individual commands can also be restricted to specific platforms:
 version: '3'
 
 tasks:
-  build-windows:
+  build:
     cmds:
-      - cmd: echo 'Running command on windows (amd64) and darwin'
+      - cmd: echo 'Running command on Windows (amd64) and macOS'
         platforms: [windows/amd64, darwin]
       - cmd: echo 'Running on all platforms'
 ```