Change meta.rspec.behaviour to not include newline at EOL

If the newline character is included, the scope actually extends to the beginning of the next line. And if the next line then also contains a (nested) meta.rspec.behaviour scope, the two scopes will get merged and the symbol list becomes messed up.

Fixes #112

Syntaxes/RSpec.tmLanguage

@@ -107,7 +107,7 @@
 			<key>comment</key>
 			<string>Begin regexp must not match pending behaviours (see https://github.com/rspec/rspec-tmbundle/issues/31).</string>
 			<key>end</key>
-			<string>\b(do)\s*$</string>
+			<string>\b(do)(?=\s*$)</string>
 			<key>endCaptures</key>
 			<dict>
 				<key>1</key>