Fix broken links in 2.8 release notes

Some of the linked file names had underscore where they should
have hyphen.

Change-Id: Iff50312a2e56d5652f454fb92c0c0596d7717222
diff --git a/ReleaseNotes/ReleaseNotes-2.8.txt b/ReleaseNotes/ReleaseNotes-2.8.txt
index f548c39..e0288fc 100644
--- a/ReleaseNotes/ReleaseNotes-2.8.txt
+++ b/ReleaseNotes/ReleaseNotes-2.8.txt
@@ -95,10 +95,10 @@
 it is possible to configure the name of the headers used for propagating this extra
 information and enforce them on the user profile during login and beyond.
 
-* link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config_gerrit.html#_a_id_httpd_a_section_httpd[
+* link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config-gerrit.html#_a_id_httpd_a_section_httpd[
 Customizable registration page for HTTP authentication].
 
-* link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config_gerrit.html#_a_id_httpd_a_section_httpd[
+* link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config-gerrit.html#_a_id_httpd_a_section_httpd[
 Configurable external `robots.txt` file].
 
 * Support for
@@ -111,15 +111,15 @@
 link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config-auto-site-initialization.html[
 auto-initialized on server startup].
 
-* link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config_gerrit.html#httpd.filterClass[
+* link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config-gerrit.html#httpd.filterClass[
 Configurable filtering of HTTP traffic through Gerrit's HTTP protocol].
 
 * Labels can be
-link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config_labels.html#httpd.label_copyAllScoresIfNoCodeChange[
+link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config-labels.html#httpd.label_copyAllScoresIfNoCodeChange[
 configured to copy scores forward to new patch sets if there is no code change].
 
 * Labels can be
-link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config_labels.html#httpd.label_copyAllScoresOnTrivialRebase[
+link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config-labels.html#httpd.label_copyAllScoresOnTrivialRebase[
 configured to copy scores forward to new patch sets for trivial rebases].
 
 Web UI
@@ -475,7 +475,7 @@
 
 
 * The `commit-msg` hook installation command is now
-link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config_gerrit.html#gerrit.installCommitMsgHookCommand[
+link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/config-gerrit.html#gerrit.installCommitMsgHookCommand[
 configurable].
 
 * link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.8/cmd-ls-members.html[