[gitg] Escape subject commit text

[Alberto Fanjul <albfan src gnome org>]

commit 5aed45af743b425b990b34e2069f2f865dcc99a5
Author: Rostyslav Arkadiev <rostyslav arkadiev gmail com>
Date:   Mon Nov 18 01:54:48 2019 +0200

    Escape subject commit text
    
    Fixes #256

 libgitg/gitg-diff-view-commit-details.vala | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/libgitg/gitg-diff-view-commit-details.vala b/libgitg/gitg-diff-view-commit-details.vala
index df2cc865..574b6c14 100644
--- a/libgitg/gitg-diff-view-commit-details.vala
+++ b/libgitg/gitg-diff-view-commit-details.vala
@@ -185,7 +185,7 @@ class Gitg.DiffViewCommitDetails : Gtk.Grid
                        return;
                }
 
-               d_label_subject.label = parse_links_on_subject(commit.get_subject());
+               d_label_subject.label = subject_to_markup(commit.get_subject());
                d_label_sha1.label = commit.get_id().to_string();
 
                var author = commit.get_author();
@@ -256,6 +256,11 @@ class Gitg.DiffViewCommitDetails : Gtk.Grid
                update_avatar();
        }
 
+       private string subject_to_markup(string subject_text)
+       {
+               return Markup.escape_text(parse_links_on_subject(subject_text));
+       }
+
        private string parse_links_on_subject(string subject_text)
        {
                string result = subject_text.dup();