[docs] Fix indentation of commands

DocBook outputs the extra spacing before the commands verbatim.

docs/usermanual-install-harfbuzz.xml

@@ -50,13 +50,9 @@
     </para>
     <para>
       For example, on an Ubuntu or Debian system, you would run:
-      <programlisting>
-	<command>sudo apt install</command> <package>gcc g++ libfreetype6-dev libglib2.0-dev libcairo2-dev</package>
-      </programlisting>
+      <programlisting><command>sudo apt install</command> <package>gcc g++ libfreetype6-dev libglib2.0-dev libcairo2-dev</package></programlisting>
       On Fedora, RHEL, CentOS, or other Red-Hat&ndash;based systems, you would run:
-      <programlisting>
-	<command>sudo yum install</command> <package>gcc gcc-c++ freetype-devel glib2-devel cairo-devel</package>
-      </programlisting>
+      <programlisting><command>sudo yum install</command> <package>gcc gcc-c++ freetype-devel glib2-devel cairo-devel</package></programlisting>
 
     </para>
     
@@ -89,13 +85,9 @@
     </para>
     <para>
       On Ubuntu or Debian, run:
-      <programlisting>
-	<command>sudo apt-get install</command> <package>meson pkg-config gtk-doc-tools</package>
-      </programlisting>
+      <programlisting><command>sudo apt-get install</command> <package>meson pkg-config gtk-doc-tools</package></programlisting>
       On Fedora, RHEL, CentOS, run:
-      <programlisting>
-	<command>sudo yum install</command> <package>meson pkgconfig gtk-doc</package>
-      </programlisting>
+      <programlisting><command>sudo yum install</command> <package>meson pkgconfig gtk-doc</package></programlisting>
       
     </para>
     <para>
@@ -128,15 +120,11 @@
 	<emphasis>(1)</emphasis> You must first install the
 	development packages for FreeType, Cairo, and GLib. If you are
 	using MacPorts, you should run:
-      <programlisting>
-	<command>sudo port install</command> <package>freetype glib2 cairo</package>
-      </programlisting>
+      <programlisting><command>sudo port install</command> <package>freetype glib2 cairo</package></programlisting>
       </para>
       <para>
 	If you are using Homebrew, you should run:
-	<programlisting>	
-	  <command>brew install</command> <package>freetype glib cairo</package>
-	</programlisting>
+	<programlisting><command>brew install</command> <package>freetype glib cairo</package></programlisting>
       </para>
       <para>
 	<emphasis>(2)</emphasis> The next step depends on whether you are building from the
@@ -147,13 +135,9 @@
 	<emphasis>(2)(a)</emphasis> If you are installing HarfBuzz
 	from a downloaded tarball release, extract the tarball and
 	open a Terminal in the extracted source-code directory. Run:
-	<programlisting>
-	  <command>meson build</command>
-	</programlisting>
+	<programlisting><command>meson build</command></programlisting>
 	followed by:
-	<programlisting>	
-	  <command>meson compile -C build</command>
-	</programlisting>
+	<programlisting><command>meson compile -C build</command></programlisting>
 	to build HarfBuzz.
       </para>
       <para>
@@ -164,30 +148,20 @@
       </para>
       <para>If you are
 	using MacPorts, you should run:
-      <programlisting>
-	<command>sudo port install</command> <package>meson pkgconfig gtk-doc</package> 
-      </programlisting>
+      <programlisting><command>sudo port install</command> <package>meson pkgconfig gtk-doc</package></programlisting>
       to install the build dependencies.
       </para>
       <para>If you are using Homebrew, you should run:
-	<programlisting>	
-	  <command>brew install</command> <package>meson pkgconfig gtk-doc</package>
-	</programlisting>
+	<programlisting><command>brew install</command> <package>meson pkgconfig gtk-doc</package></programlisting>
       	Finally, you can run:
-	<programlisting>
-	  <command>meson build</command>
-	</programlisting>
+	<programlisting><command>meson build</command></programlisting>
       </para>
       <para>
 	<emphasis>(3)</emphasis> You can now build HarfBuzz (on either
 	a MacPorts or a Homebrew system) by running:
-	<programlisting>
-	  <command>meson build</command>
-	</programlisting>
+	<programlisting><command>meson build</command></programlisting>
 	followed by:
-	<programlisting>
-	  <command>meson compile -C build</command>
-	</programlisting>
+	<programlisting><command>meson compile -C build</command></programlisting>
       </para>
       <para>
 	This should leave you with a shared