[valadoc] libvaladoc: Fix some -Wincompatible-pointer-types warnings

[Rico Tzschichholz <ricotz src gnome org>]

commit 0401c298bf4c8dd018ccd8e4f95e2f99c8e112ff
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Sat Aug 26 14:52:44 2017 +0200

    libvaladoc: Fix some -Wincompatible-pointer-types warnings

 .../documentation/gtkdocmarkdownparser.vala        |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/src/libvaladoc/documentation/gtkdocmarkdownparser.vala 
b/src/libvaladoc/documentation/gtkdocmarkdownparser.vala
index ff52e95..e66a934 100644
--- a/src/libvaladoc/documentation/gtkdocmarkdownparser.vala
+++ b/src/libvaladoc/documentation/gtkdocmarkdownparser.vala
@@ -686,11 +686,11 @@ public class Valadoc.Gtkdoc.MarkdownParser : Object, ResourceLocator {
        }
 
 
-       private void add_text (Valadoc.Token token) {
+       private void add_text (Valadoc.Token token) throws ParserError {
                add_content_string (token.to_string ());
        }
 
-       private void add_value (Valadoc.Token token) {
+       private void add_value (Valadoc.Token token) throws ParserError {
                assert (token.value != null);
 
                add_content_string (token.value);
@@ -716,7 +716,7 @@ public class Valadoc.Gtkdoc.MarkdownParser : Object, ResourceLocator {
                push (run);
        }
 
-       private void preserve_token (Valadoc.Token token) {
+       private void preserve_token (Valadoc.Token token) throws ParserError {
                assert (preserved_token == null);
                preserved_token = token;
        }