doc: Manually insert some anchors

doc/manual/src/advanced-topics/diff-hook.md

@@ -101,7 +101,7 @@ In particular, notice the
 `/nix/store/krpqk0l9ib0ibi1d2w52z293zw455cap-unstable.check` output. Nix
 has copied the build results to that directory where you can examine it.
 
-> **Note**
+> []{#check-dirs-are-unregistered} **Note**
 > 
 > Check paths are not protected against garbage collection, and this
 > path will be deleted on the next garbage collection.

doc/manual/src/command-ref/nix-store.md

@@ -22,7 +22,7 @@ This section lists the options that are common to all operations. These
 options are allowed for every subcommand, though they may not always
 have an effect.
 
-  - `--add-root` *path*\
+  - [`--add-root`]{#opt-add-root} *path*\
     Causes the result of a realisation (`--realise` and
     `--force-realise`) to be registered as a root of the garbage
     collector. *path* will be created as a symlink to the resulting

doc/manual/src/expressions/derivations.md

@@ -4,7 +4,7 @@ The most important built-in function is `derivation`, which is used to
 describe a single derivation (a build action). It takes as input a set,
 the attributes of which specify the inputs of the build.
 
-  - There must be an attribute named `system` whose value must be a
+  - There must be an attribute named [`system`]{#attr-system} whose value must be a
     string specifying a Nix system type, such as `"i686-linux"` or
     `"x86_64-darwin"`. (To figure out your system type, run `nix -vv
     --version`.) The build can only be performed on a machine and

doc/manual/src/installation/installing-binary.md

@@ -186,7 +186,8 @@ and `/etc/zshrc` which you may remove.
 > read-only root will prevent you from manually deleting the empty `/nix`
 > mountpoint.
 
-# macOS Installation <a name="sect-macos-installation-change-store-prefix"></a><a name="sect-macos-installation-encrypted-volume"></a><a name="sect-macos-installation-symlink"></a><a name="sect-macos-installation-recommended-notes"></a>
+# macOS Installation
+[]{#sect-macos-installation-change-store-prefix}[]{#sect-macos-installation-encrypted-volume}[]{#sect-macos-installation-symlink}[]{#sect-macos-installation-recommended-notes}
 <!-- Note: anchors above to catch permalinks to old explanations -->
 
 We believe we have ironed out how to cleanly support the read-only root