docs/manual/br2-external: remove superfluous leading space in code blocks

They are not needed, and other code blocks in the same file are not
indented either.

Remove those leading spaces, so all our code blocks look the same.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

docs/manual/customize-outside-br.txt

@@ -33,27 +33,27 @@ to the Buildroot output directory.
 Some examples:
 
 -----
- buildroot/ $ make BR2_EXTERNAL=/path/to/foobar menuconfig
+buildroot/ $ make BR2_EXTERNAL=/path/to/foobar menuconfig
 -----
 
 From now on, external definitions from the +/path/to/foobar+
 directory will be used:
 
 -----
- buildroot/ $ make
- buildroot/ $ make legal-info
+buildroot/ $ make
+buildroot/ $ make legal-info
 -----
 
 We can switch to another external definitions directory at any time:
 
 -----
- buildroot/ $ make BR2_EXTERNAL=/where/we/have/barfoo xconfig
+buildroot/ $ make BR2_EXTERNAL=/where/we/have/barfoo xconfig
 -----
 
 Or disable the usage of external definitions:
 
 -----
- buildroot/ $ make BR2_EXTERNAL= xconfig
+buildroot/ $ make BR2_EXTERNAL= xconfig
 -----
 
 +BR2_EXTERNAL+ allows three different things: