Merge pull request #3159 from earksiinni/docs-import-brackets

Document import <path> syntax

doc/manual/expressions/builtins.xml

@@ -746,6 +746,11 @@ builtins.genList (x: x * x) 5
     separate file, and use it from Nix expressions in other
     files.</para>
 
+    <note><para>Unlike some languages, <function>import</function> is a regular
+    function in Nix. Paths using the angle bracket syntax (e.g., <function>
+    import</function> <replaceable>&lt;foo&gt;</replaceable>) are normal path
+    values (see <xref linkend='ssec-values' />).</para></note>
+
     <para>A Nix expression loaded by <function>import</function> must
     not contain any <emphasis>free variables</emphasis> (identifiers
     that are not defined in the Nix expression itself and are not