about.md: Fix the example URLs to the rendered HTML output

Change-Id: Ia71aad07d3fa5b84f966094b7ac5f08d04c2c554

src/main/resources/Documentation/about.md

diff --git a/src/main/resources/Documentation/about.md b/src/main/resources/Documentation/about.md
index ef74e0b..2749ff4 100644
--- a/src/main/resources/Documentation/about.md
+++ b/src/main/resources/Documentation/about.md
@@ -2,16 +2,16 @@
 
 If projects contain documentation, e.g. as Markdown files, the plugin
 automatically serves the generated HTML under
-`/@PLUGIN@/project/<project-name>/<file-name>`. The project name must
+`/plugins/@PLUGIN@/project/<project-name>/<file-name>`. The project name must
 be URL encoded.
 
 The file is served from the branch/commit to which `HEAD` points unless
 a revision is specified in the URL as
-`/@PLUGIN@/project/<project-name>/rev/<rev>/<file-name>`. The revision
+`/plugins/@PLUGIN@/project/<project-name>/rev/<rev>/<file-name>`. The revision
 must be URL encoded.
 
 ```
-  /@PLUGIN@/project/external%2Fopenssl/rev/stable-1.3/docs/faq.md
+  /plugins/@PLUGIN@/project/external%2Fopenssl/rev/stable-1.3/docs/faq.md
 ```
 
 `rev` can be any ref or commit that is visible to the calling user.
@@ -23,7 +23,7 @@
 unformatted text.
 
 ```
-  /@PLUGIN@/project/external%2Fopenssl/rev/stable-1.3/docs/faq.md?raw
+  /plugins/@PLUGIN@/project/external%2Fopenssl/rev/stable-1.3/docs/faq.md?raw
 ```
 
 The `raw` parameter cannot be used for binary files.