Expose message prettification

This is useful outside of our command-emulating methods, so let a user prettify as much as they want.

Author: carlosmn

LibGit2Sharp.Tests/CommitFixture.cs

@@ -1045,5 +1045,15 @@ public void CanNotAmendACommitInAWayThatWouldLeadTheNewCommitToBecomeEmpty()
 newCommitOptions{AmendPreviousCommit=true}));
 }
 }
+
+[Fact]
+publicvoidCanPrettifyAMessage()
+{
+stringinput="# Comment\nA line that will remain\n# And another character\n\n\n";
+stringexpected="A line that will remain\n";
+
+Assert.Equal(expected,Commit.PrettifyMessage(input,'#'));
+Assert.Equal(expected,Commit.PrettifyMessage(input.Replace('#',''),''));
+}
 }
 }

LibGit2Sharp/Commit.cs

@@ -113,6 +113,20 @@ private static string RetrieveEncodingOf(ObjectHandle obj)
 returnencoding??"UTF-8";
 }
 
+/// <summary>
+/// Prettify a commit message
+/// <para>
+/// Remove comment lines and trailing lines
+/// </para>
+/// </summary>
+/// <returns>The prettified message</returns>
+/// <param name="message">The message to prettify.</param>
+/// <param name="commentChar">Comment character. Lines starting with it will be removed</param>
+publicstaticstringPrettifyMessage(stringmessage,charcommentChar)
+{
+returnProxy.git_message_prettify(message,commentChar);
+}
+
 privatestringDebuggerDisplay
 {
 get