doc: fix spurious whitespace

doc/contributing.xml

@@ -12,9 +12,9 @@ xlink:href="https://github.com/NixOS/nixpkgs/tree/master/doc">doc</filename>
   You can quickly check your edits with <command>make</command>:
  </para>
 <screen>
-  $ cd /path/to/nixpkgs/doc
-  $ nix-shell
-  [nix-shell]$ make
+<prompt>$ </prompt>cd /path/to/nixpkgs/doc
+<prompt>$ </prompt>nix-shell
+<prompt>[nix-shell]$ </prompt>make
 </screen>
  <para>
   If you experience problems, run <command>make debug</command> to help
@@ -24,10 +24,10 @@ xlink:href="https://github.com/NixOS/nixpkgs/tree/master/doc">doc</filename>
   After making modifications to the manual, it's important to build it before
   committing. You can do that as follows:
 <screen>
-  $ cd /path/to/nixpkgs/doc
-  $ nix-shell
-  [nix-shell]$ make clean
-  [nix-shell]$ nix-build .
+<prompt>$ </prompt>cd /path/to/nixpkgs/doc
+<prompt>$ </prompt>nix-shell
+<prompt>[nix-shell]$ </prompt>make clean
+<prompt>[nix-shell]$ </prompt>nix-build .
 </screen>
   If the build succeeds, the manual will be in
   <filename>./result/share/doc/nixpkgs/manual.html</filename>.

doc/functions/prefer-remote-fetch.xml

@@ -15,11 +15,11 @@
 </programlisting>
   A full configuration example for that sets the overlay up for your own
   account, could look like this
-<programlisting>
-    $ mkdir ~/.config/nixpkgs/overlays/
-    $ cat &gt; ~/.config/nixpkgs/overlays/prefer-remote-fetch.nix &lt;&lt;EOF
+<screen>
+<prompt>$ </prompt>mkdir ~/.config/nixpkgs/overlays/
+<prompt>$ </prompt>cat &gt; ~/.config/nixpkgs/overlays/prefer-remote-fetch.nix &lt;&lt;EOF
   self: super: super.prefer-remote-fetch self super
 EOF
-  </programlisting>
+</screen>
  </para>
 </section>

doc/languages-frameworks/beam.xml

@@ -330,13 +330,13 @@ $ nix-env -f "<nixpkgs>" -iA beamPackages.ibrowse
     could do the following:
    </para>
 
-<programlisting>
-      $ nix-shell -A beamPackages.ibrowse.env --run "erl"
-      Erlang/OTP 18 [erts-7.0] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]
+<screen>
+<prompt>$ </prompt><userinput>nix-shell -A beamPackages.ibrowse.env --run "erl"</userinput>
+<computeroutput>Erlang/OTP 18 [erts-7.0] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]
 
-      Eshell V7.0  (abort with ^G)
-      1> m(ibrowse).
-      Module: ibrowse
+Eshell V7.0  (abort with ^G)</computeroutput>
+<prompt>1> </prompt><userinput>m(ibrowse).</userinput>
+<computeroutput>Module: ibrowse
 MD5: 3b3e0137d0cbb28070146978a3392945
 Compiled: January 10 2016, 23:34
 Object file: /nix/store/g1rlf65rdgjs4abbyj4grp37ry7ywivj-ibrowse-4.2.2/lib/erlang/lib/ibrowse-4.2.2/ebin/ibrowse.beam
@@ -368,9 +368,9 @@ $ nix-env -f &quot;&lt;nixpkgs&gt;&quot; -iA beamPackages.ibrowse
 send_req_direct/5             trace_off/2
 send_req_direct/6             trace_on/0
 trace_on/2
-      ok
-      2>
-    </programlisting>
+ok</computeroutput>
+<prompt>2></prompt>
+</screen>
 
    <para>
     Notice the <literal>-A beamPackages.ibrowse.env</literal>. That is the key
@@ -513,9 +513,9 @@ analyze: build plt
    <literal>nixpkgs</literal> repository:
   </para>
 
-<programlisting>
-$ nix-build -A beamPackages
-    </programlisting>
+<screen>
+<prompt>$ </prompt>nix-build -A beamPackages
+</screen>
 
   <para>
    That will attempt to build every package in <literal>beamPackages</literal>.

doc/languages-frameworks/go.xml

@@ -218,11 +218,11 @@ deis = buildGoPackage rec {
    <varname>bin</varname> includes program binaries. You can test build a Go
    binary as follows:
 <screen>
-    $ nix-build -A deis.bin
+<prompt>$ </prompt>nix-build -A deis.bin
 </screen>
    or build all outputs with:
 <screen>
-    $ nix-build -A deis.all
+<prompt>$ </prompt>nix-build -A deis.all
 </screen>
    <varname>bin</varname> output will be installed by default with
    <varname>nix-env -i</varname> or <varname>systemPackages</varname>.