Rename doc/manual{src -> source}

This is needed to avoid this
https://github.com/mesonbuild/meson/issues/13774 when we go back to
making our subproject directory `src`.

doc/manual/source/command-ref/nix-store/delete.md

@@ -0,0 +1,33 @@
+# Name
+
+`nix-store --delete` - delete store paths
+
+# Synopsis
+
+`nix-store` `--delete` [`--ignore-liveness`] *paths…*
+
+# Description
+
+The operation `--delete` deletes the store paths *paths* from the Nix
+store, but only if it is safe to do so; that is, when the path is not
+reachable from a root of the garbage collector. This means that you can
+only delete paths that would also be deleted by `nix-store --gc`. Thus,
+`--delete` is a more targeted version of `--gc`.
+
+With the option `--ignore-liveness`, reachability from the roots is
+ignored. However, the path still won’t be deleted if there are other
+paths in the store that refer to it (i.e., depend on it).
+
+{{#include ./opt-common.md}}
+
+{{#include ../opt-common.md}}
+
+{{#include ../env-common.md}}
+
+# Example
+
+```console
+$ nix-store --delete /nix/store/zq0h41l75vlb4z45kzgjjmsjxvcv1qk7-mesa-6.4
+0 bytes freed (0.00 MiB)
+error: cannot delete path `/nix/store/zq0h41l75vlb4z45kzgjjmsjxvcv1qk7-mesa-6.4' since it is still alive
+```