List{Branches,Tags}: Use "-S' as alias for "--start" instead of "-s"

Using upper case "-S" makes the API consistent with the other list
APIS:

- list changes
- list groups
- list projects

This will break any existing clients that use -s, but there are no
known clients doing that except the GWT UI (fixed in this change) and
the PolyGerrit UI (will be fixed in a follow-up change on master).

Change-Id: Ic9c73eb50c537957a14ab180cb5d5bbfa6c6f50d

Documentation/rest-api-projects.txt

@@ -1164,7 +1164,7 @@ Limit the number of branches to be included in the results.
   ]
 ----
 
-Skip(s)::
+Skip(S)::
 Skip the given number of branches from the beginning of the list.
 +
 .Request
@@ -1842,7 +1842,7 @@ Limit the number of tags to be included in the results.
   ]
 ----
 
-Skip(s)::
+Skip(S)::
 Skip the given number of tags from the beginning of the list.
 +
 .Request

gerrit-gwtui/src/main/java/com/google/gerrit/client/projects/ProjectApi.java

@@ -49,7 +49,7 @@ public class ProjectApi {
       Project.NameKey name, String viewName, int limit, int start, String match) {
     RestApi call = project(name).view(viewName);
     call.addParameter("n", limit);
-    call.addParameter("s", start);
+    call.addParameter("S", start);
     if (match != null) {
       if (match.startsWith("^")) {
         call.addParameter("r", match);

gerrit-server/src/main/java/com/google/gerrit/server/project/ListBranches.java

@@ -62,7 +62,7 @@ public class ListBranches implements RestReadView<ProjectResource> {
 
   @Option(
     name = "--start",
-    aliases = {"-s"},
+    aliases = {"-S"},
     metaVar = "CNT",
     usage = "number of branches to skip"
   )

gerrit-server/src/main/java/com/google/gerrit/server/project/ListTags.java

@@ -70,7 +70,7 @@ public class ListTags implements RestReadView<ProjectResource> {
 
   @Option(
     name = "--start",
-    aliases = {"-s"},
+    aliases = {"-S"},
     metaVar = "CNT",
     usage = "number of tags to skip"
   )