Update doc/manual/src/command-ref/env-common.md

Co-authored-by: Eelco Dolstra <edolstra@gmail.com>

doc/manual/src/command-ref/env-common.md

@@ -48,7 +48,7 @@ Most Nix commands interpret the following environment variables:
 
     1. `$HOME/.nix-defexpr/channels`
     2. `/nix/var/nix/profiles/per-user/root/channels/nixpkgs`
-    3. `/nix/var/nix/profiles/per-user/root/channels.`
+    3. `/nix/var/nix/profiles/per-user/root/channels`
 
   - [`NIX_IGNORE_SYMLINK_STORE`]{#env-NIX_IGNORE_SYMLINK_STORE}\
     Normally, the Nix store directory (typically `/nix/store`) is not