Change docs links to actual file extension (.md)

See https://gerrit-review.googlesource.com/83950 for detailed context.

Change-Id: Iae3b8851c65fa32d038e8a74e5d934c67e1142f2

src/main/resources/Documentation/cmd-branch.md

diff --git a/src/main/resources/Documentation/cmd-branch.md b/src/main/resources/Documentation/cmd-branch.md
index d22bbda..a9ab868 100644
--- a/src/main/resources/Documentation/cmd-branch.md
+++ b/src/main/resources/Documentation/cmd-branch.md
@@ -57,4 +57,4 @@
 
 SEE ALSO
 --------
-* [@PLUGIN@ tag SSH command](cmd-tag.html)
+* [@PLUGIN@ tag SSH command](cmd-tag.md)

src/main/resources/Documentation/cmd-tag.md

diff --git a/src/main/resources/Documentation/cmd-tag.md b/src/main/resources/Documentation/cmd-tag.md
index bff73cf..c32fdcd 100644
--- a/src/main/resources/Documentation/cmd-tag.md
+++ b/src/main/resources/Documentation/cmd-tag.md
@@ -48,4 +48,4 @@
 
 SEE ALSO
 --------
-* [@PLUGIN@ branch SSH command](cmd-branch.html)
\ No newline at end of file
+* [@PLUGIN@ branch SSH command](cmd-branch.md)

src/main/resources/Documentation/rest-api-branch.md

diff --git a/src/main/resources/Documentation/rest-api-branch.md b/src/main/resources/Documentation/rest-api-branch.md
index 67f138d..7580424 100644
--- a/src/main/resources/Documentation/rest-api-branch.md
+++ b/src/main/resources/Documentation/rest-api-branch.md
@@ -74,4 +74,4 @@
 
 SEE ALSO
 --------
-* [/tag REST endpoint](rest-api-tag.html)
\ No newline at end of file
+* [/tag REST endpoint](rest-api-tag.md)

src/main/resources/Documentation/rest-api-tag.md

diff --git a/src/main/resources/Documentation/rest-api-tag.md b/src/main/resources/Documentation/rest-api-tag.md
index 4648301..4b0a7a5 100644
--- a/src/main/resources/Documentation/rest-api-tag.md
+++ b/src/main/resources/Documentation/rest-api-tag.md
@@ -74,4 +74,4 @@
 
 SEE ALSO
 --------
-* [/branch REST endpoint](rest-api-branch.html)
\ No newline at end of file
+* [/branch REST endpoint](rest-api-branch.md)