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/release-notes/rl-1.6.1.md

@@ -0,0 +1,32 @@
+# Release 1.6.1 (2013-10-28)
+
+This is primarily a bug fix release. Changes of interest are:
+
+  - Nix 1.6 accidentally changed the semantics of antiquoted paths in
+    strings, such as `"${/foo}/bar"`. This release reverts to the Nix
+    1.5.3 behaviour.
+
+  - Previously, Nix optimised expressions such as `"${expr}"` to *expr*.
+    Thus it neither checked whether *expr* could be coerced to a string,
+    nor applied such coercions. This meant that `"${123}"` evaluatued to
+    `123`, and `"${./foo}"` evaluated to `./foo` (even though `"${./foo}
+    "` evaluates to `"/nix/store/hash-foo "`). Nix now checks the type
+    of antiquoted expressions and applies coercions.
+
+  - Nix now shows the exact position of undefined variables. In
+    particular, undefined variable errors in a `with` previously didn't
+    show *any* position information, so this makes it a lot easier to
+    fix such errors.
+
+  - Undefined variables are now treated consistently. Previously, the
+    `tryEval` function would catch undefined variables inside a `with`
+    but not outside. Now `tryEval` never catches undefined variables.
+
+  - Bash completion in `nix-shell` now works correctly.
+
+  - Stack traces are less verbose: they no longer show calls to builtin
+    functions and only show a single line for each derivation on the
+    call stack.
+
+  - New built-in function: `builtins.typeOf`, which returns the type of
+    its argument as a string.