Update the "'=' to ':' in attributes" fix-it to include a space.

...because it was bugging me, and because the migrator uses it.

Author: jrose-apple

lib/Parse/ParseDecl.cpp

@@ -361,14 +361,15 @@ bool Parser::parseNewDeclAttribute(DeclAttributes &Attributes, SourceLoc AtLoc,
 
 
   // Check 'Tok', return false if ':' or '=' cannot be found.
-  // Complain if '=' is found and suggest replacing it with ':'.
+  // Complain if '=' is found and suggest replacing it with ": ".
   auto findAttrValueDelimiter = [&]() -> bool {
     if (!Tok.is(tok::colon)) {
       if (!Tok.is(tok::equal))
         return false;
-      else
-        diagnose(Tok.getLoc(), diag::replace_equal_with_colon_for_value)
-          .fixItReplace(Tok.getLoc(), ":");
+
+      bool wantSpace = (Tok.getRange().getEnd() == peekToken().getLoc());
+      diagnose(Tok.getLoc(), diag::replace_equal_with_colon_for_value)
+        .fixItReplace(Tok.getLoc(), wantSpace ? ": " : ":");
     }
     return true;
   };

test/attr/attr_availability.swift

@@ -145,6 +145,12 @@ let _: Int
 @available(*, deprecated, unavailable, message: "message") // expected-error{{'available' attribute cannot be both unconditionally 'unavailable' and 'deprecated'}}
 struct BadUnconditionalAvailability { };
 
+@available(*, unavailable, message="oh no you don't") // expected-error {{'=' has been replaced with ':' in attribute arguments}} {{35-36=: }}
+typealias EqualFixIt1 = Int
+@available(*, unavailable, message = "oh no you don't") // expected-error {{'=' has been replaced with ':' in attribute arguments}} {{36-37=:}}
+typealias EqualFixIt2 = Int
+
+
 // Encoding in messages
 @available(*, deprecated, message: "Say \"Hi\"")
 func deprecated_func_with_message() {}