Fix duplicate links in document

Two sections have the same link [[get-content]]. When click from the
toc, all will direct to the first section.

Change-Id: Iefaeab5887c5121f9bdbc7a00413bfded3d66021
diff --git a/Documentation/rest-api-projects.txt b/Documentation/rest-api-projects.txt
index 45d33ae..3baaaa8 100644
--- a/Documentation/rest-api-projects.txt
+++ b/Documentation/rest-api-projects.txt
@@ -1537,7 +1537,7 @@
   }
 ----
 
-[[get-content]]
+[[get-content-from-commit]]
 === Get Content
 --
 'GET /projects/link:#project-name[\{project-name\}]/commits/link:#commit-id[\{commit-id\}]/files/link:rest-api-changes.html#file-id[\{file-id\}]/content'