Only enhancement of formatting.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* doc/gnat_ugn/gnat_and_program_execution.rst,
	doc/gnat_ugn/gnat_utility_programs.rst,
	doc/gnat_ugn/inline_assembler.rst: Fix typos and formatting
	glitches.
	* gnat_ugn.texi: Regenerate.