doc: style: report indentation of multi-line condition

To help readability and discriminate the 'then' block from the
multi-line condition, suggest to increase the indentation of the
condition.

Change-Id: I02e3834be3001e7ecf24349ad3cefe94b27b79c8
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8199
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Tested-by: jenkins
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>

doc/manual/style.txt

@@ -97,6 +97,21 @@ OpenOCD project.
       x = 0;
   }
   @endcode
+- on <tt> if </tt> statements where the condition is split among multiple
+  lines, increase the indentation of the condition to prevent it to match
+  to the indentation of the <tt> then </tt> block due to length of 'if ('
+  being same of the TAB width of 4 characters. Use:
+  @code
+  if (CMD_ARGC < 3
+          || CMD_ARGC > 8)
+      return ERROR_COMMAND_SYNTAX_ERROR;
+  @endcode
+  instead of:
+  @code
+  if (CMD_ARGC < 3 ||
+      CMD_ARGC > 8)
+      return ERROR_COMMAND_SYNTAX_ERROR;
+  @endcode
 
 Finally, try to avoid lines of code that are longer than 72-80 columns: