Clarify .hg directory

pages/common/hg-clone.md

@@ -10,7 +10,7 @@
 
 `hg clone --branch {{branch}} {{remote_repository_source}}`
 
-- Clone a repository with only the .hg directory, without checking out files:
+- Clone a repository with only the ".hg" directory, without checking out files:
 
 `hg clone --noupdate {{remote_repository_source}}`