Add a 5.0 preview invitation (#212)

Author: michaelblyons

messages.json

@@ -1,3 +1,4 @@
 {
-	"3.1.1": "messages/prerelease-invitation.md"
+	"4.2.0": "messages/5.0.0-prerelease-invitation.md",
+	"3.1.1": "messages/4.0.0-prerelease-invitation.md"
 }

messages/prerelease-invitation.md messages/4.0.0-prerelease-invitation.mdmessages/prerelease-invitation.md renamed to messages/4.0.0-prerelease-invitation.md

@@ -6,7 +6,7 @@ languages. This means your color scheme should start highlighting
 similar concepts the same colors as you are used to in those other
 languages.
 
-It is not perfect. And, as such, I'm inviting adventurous ST users to
+It is not perfect. And as such, I'm inviting adventurous ST users to
 try it out ahead of time. If that sounds like you, open your Package
 Control Settings (usually `Cmd/Ctrl`+`Shift`+`P`, "Preferences: Package
 Control Settings") and add `"PowerShell"` to the array for
@@ -17,4 +17,4 @@ highlighting further down in the file, please mention them at
 https://github.com/SublimeText/PowerShell/issues and include "v4" in
 the title.
 
-Thank you. Be well.
+Thank you.

messages/5.0.0-prerelease-invitation.md

@@ -0,0 +1,46 @@
+# Prelease invitation
+
+Hello PowerShell user. There are improvements underway to parse PS
+more consistently in Sublime Test. Some of these changes have the
+potential for regressions. A summary of changes is below.
+
+It is not perfect. And as such, I'm inviting adventurous ST users to
+try it out ahead of time. If that sounds like you, open your Package
+Control Settings (usually `Cmd/Ctrl`+`Shift`+`P`, "Preferences: Package
+Control Settings") and add `"PowerShell"` to the array for
+`install_prereleases` in the right-hand pane.
+
+If you find bugs, especially egregious ones that break code
+highlighting further down in the file, please mention them at
+https://github.com/SublimeText/PowerShell/issues and include "v5" in
+the title.
+
+Thank you.
+
+
+## Standout Improvements
+
+- Commands not in Verb-Noun format are now recognized.
+
+- Command arguments are more conscientiously marked,
+  including unquoted strings.
+
+- String contents are sometimes interpreted specially,
+  though not in all cases. Some examples:
+
+    * Here-strings beginning with `using System` are
+      highlighted with C#.
+
+    * Command argument strings recognize wildcards and
+      path separators.
+
+    * Single-quoted strings in certain cases are
+      highlighted with Regular Expressions.
+
+    * Other strings recognize formatting placeholders.
+
+- `using` imports can only come at the beginning of a file.
+
+- `meta` scopes are used in more places, which doesn't
+  typically affect highlighting, but sometimes has an
+  effect on ST commands.