handle escaped spaces in tokens + filepaths in completions

ast/lex.go

@@ -164,6 +164,15 @@ func lex(input string) *Token {
         case ';':
             i = matchLineEnd(i)
             start_pos = i + 1
+
+        // this isnt to handle string escaping
+        // its only to make sure that escaped spaces stay in
+        // the same token.
+        case '\\':
+            if i != len(input) - 1 && input[i+1] == ' '{
+                // eat the backslash
+                input = input[:i] + input[i+1:]
+            }
         }
 
         if needs_alloc {