Improve sublime arm name indexing.

The previous definition included the leading ++ in the
indexed name, which thwarts "Goto Definition". This also
tweaks the pattern to include arms defined with +-.

extras/hoonSublime/hoon.YAML-tmLanguage

@@ -32,8 +32,9 @@ patterns:
   name: constant.character.hoon
   match: "[a-z]([a-z0-9-]*[a-z0-9])?/"
 - comment: arm
-  name: entity.name.function.hoon
-  match: "\\+\\+  [a-z]([a-z0-9-]*[a-z0-9])?"
+  contentName: entity.name.function.hoon
+  begin: "\\+[-+]  (?=[a-z]([a-z0-9-]*[a-z0-9])?)"
+  end: "(?![a-z0-9-])"
 - comment: cube
   name: constant.character.hoon
   match: "%[a-z]([a-z0-9-]*[a-z0-9])?"

extras/hoonSublime/hoon.tmLanguage

@@ -84,12 +84,14 @@
 			<string>constant.character.hoon</string>
 		</dict>
 		<dict>
+			<key>begin</key>
+			<string>\+[-+]  (?=[a-z]([a-z0-9-]*[a-z0-9])?)</string>
 			<key>comment</key>
 			<string>arm</string>
-			<key>match</key>
-			<string>\+\+  [a-z]([a-z0-9-]*[a-z0-9])?</string>
-			<key>name</key>
+			<key>contentName</key>
 			<string>entity.name.function.hoon</string>
+			<key>end</key>
+			<string>(?![a-z0-9-])</string>
 		</dict>
 		<dict>
 			<key>comment</key>