doc: Update architecture diagram to point to main (#28327)

* doc: Update architecture diagram to point to main

Many of the links were pointing to `master` branches for the repos which
are very behind their `main` counterparts.

Exceptions were Zoekt and deploy-sourcegraph repos

* doc: Update one more dated link to syntect server

Author: danieldides

doc/dev/background-information/architecture/architecture.dot

@@ -62,13 +62,13 @@ digraph architecture {
             shape="box3d"
             label="frontend"
             fillcolor="#7e78dc"
-            URL="https://github.com/sourcegraph/sourcegraph/tree/master/cmd/frontend"
+            URL="https://github.com/sourcegraph/sourcegraph/tree/main/cmd/frontend"
         ]
 
         worker [
             label="worker"
             fillcolor="#22ffff"
-            URL="https://github.com/sourcegraph/sourcegraph/tree/master/enterprise/cmd/worker"
+            URL="https://github.com/sourcegraph/sourcegraph/tree/main/enterprise/cmd/worker"
         ]
 
         subgraph cluster_internal_services {
@@ -101,12 +101,12 @@ digraph architecture {
                     label="searcher"
                     shape="box3d"
                     fillcolor="#e2a8fd"
-                    URL="https://github.com/sourcegraph/sourcegraph/tree/master/cmd/searcher"
+                    URL="https://github.com/sourcegraph/sourcegraph/tree/main/cmd/searcher"
                 ]
                 query_runner [
                     label="query runner"
                     fillcolor="#aaffff"
-                    URL="https://github.com/sourcegraph/sourcegraph/tree/master/cmd/query-runner"
+                    URL="https://github.com/sourcegraph/sourcegraph/tree/main/cmd/query-runner"
                 ]
             }
 
@@ -118,40 +118,40 @@ digraph architecture {
                     label="precise-code-intel-worker"
                     shape="box3d"
                     fillcolor="#eac1c1"
-                    URL="https://github.com/sourcegraph/sourcegraph/tree/master/enterprise/cmd/precise-code-intel-worker"
+                    URL="https://github.com/sourcegraph/sourcegraph/tree/main/enterprise/cmd/precise-code-intel-worker"
                 ]
 
                 symbols [
                     label="symbols"
                     shape="box3d"
                     fillcolor="#c1eaea"
-                    URL="https://github.com/sourcegraph/sourcegraph/tree/master/cmd/symbols"
+                    URL="https://github.com/sourcegraph/sourcegraph/tree/main/cmd/symbols"
                 ]
             }
 
             gitserver [
                 label="gitserver"
                 fillcolor="#cd5c5c"
                 shape="box3d"
-                URL="https://github.com/sourcegraph/sourcegraph/tree/master/cmd/gitserver"
+                URL="https://github.com/sourcegraph/sourcegraph/tree/main/cmd/gitserver"
             ]
 
             repo_updater [
                 label="repo updater"
                 fillcolor="#05a167"
-                URL="https://github.com/sourcegraph/sourcegraph/tree/master/cmd/repo-updater"
+                URL="https://github.com/sourcegraph/sourcegraph/tree/main/cmd/repo-updater"
             ]
 
             github_proxy [
                 label="github proxy"
                 fillcolor="#aaaaff"
-                URL="https://github.com/sourcegraph/sourcegraph/tree/master/cmd/github-proxy"
+                URL="https://github.com/sourcegraph/sourcegraph/tree/main/cmd/github-proxy"
             ]
 
             syntect_server [
                 label="syntect\nserver"
                 fillcolor="#cc0085"
-                URL="https://github.com/sourcegraph/syntect_server"
+                URL="https://github.com/sourcegraph/sourcegraph/tree/main/docker-images/syntax-highlighter"
             ]
         }
     }
@@ -181,7 +181,7 @@ digraph architecture {
             label="executor"
             shape="box3d"
             fillcolor="#0dc9b6"
-            URL="https://github.com/sourcegraph/sourcegraph/tree/master/enterprise/cmd/executor"
+            URL="https://github.com/sourcegraph/sourcegraph/tree/main/enterprise/cmd/executor"
         ]
     }
 

doc/dev/background-information/architecture/architecture.svg

@@ -48,7 +48,7 @@ Sourcegraph also has a fast search path for code that isn't indexed yet, or for
 
 - [searcher](https://github.com/sourcegraph/sourcegraph/blob/main/cmd/searcher/README.md) implements the non-indexed search.
 
-Syntax highlighting for any code view, including search results, is provided by [Syntect server](https://sourcegraph.com/github.com/sourcegraph/syntect_server).
+Syntax highlighting for any code view, including search results, is provided by [Syntect server](https://github.com/sourcegraph/sourcegraph/tree/main/docker-images/syntax-highlighter).
 
 If you want to learn more about search:
 

doc/dev/background-information/architecture/index.md

@@ -30,7 +30,7 @@ When introducing a new service/container we pay the cost of:
 
 - Introducing and maintaining [its Kubernetes YAML](https://github.com/sourcegraph/deploy-sourcegraph/tree/master/base).
 - Adding it to our [docker-compose deployments](https://github.com/sourcegraph/deploy-sourcegraph-docker/pull/38).
-- Integrating it as a raw process in [the single-container `sourcegraph/server` deployment mode](https://github.com/sourcegraph/sourcegraph/tree/master/cmd/server).
+- Integrating it as a raw process in [the single-container `sourcegraph/server` deployment mode](https://github.com/sourcegraph/sourcegraph/tree/main/cmd/server).
 - Documenting clearly [how it scales](https://docs.sourcegraph.com/admin/install/kubernetes/scale) alongside other services for cluster deployments.
 - Updating our [architecture diagram](https://docs.sourcegraph.com/dev/background-information/architecture).
 - Documenting the service itself in general and how site admins should manage and debug it (these needs to be done regardless of it being a new service, but if it is a new service there are additional aspects to consider.)