Documentation updates.

Author: sharpjs

README.md

@@ -1,6 +1,6 @@
 # Prequel
 
-Prequel is a minimal SQLCMD-compatible preprocessor.
+Prequel is a minimal SQLCMD-compatible preprocessor for .NET.
 
 - Adds a 'SQLCMD mode' to your project with a couple lines of code.
 - Supports `GO`, `$(var)`, `:setvar`, and `:r`.
@@ -93,6 +93,9 @@ An optional line comment may follow the directive.
 
 `$(…)` may appear anywhere, including inside other preprocessor directives.
 
+Prequel will not expand `$(…)` inside comments by default.  To enable this,
+set the preprocessor's `ExpandVariablesInComments` property to `true`.
+
 `:r` directive paths may be either absolute or relative.  **Relative paths are
 relative to the current directory**, which matches `sqlcmd.exe` behavior.  To
 use paths relative to some other directory, store the absolute path of that