[Ada] Fix unbalanced paren in documentation marker for GNAT Studio
Unbalanced parens can be found when editing in emacs using the
"check-parens" command. Offending occurrences must be examined manually,
because few of them are intentional.
Minor cleanup of typos in documentation.
gcc/ada/
* doc/gnat_rm/implementation_defined_pragmas.rst,
doc/gnat_rm/implementation_of_specific_ada_features.rst,
doc/gnat_rm/representation_clauses_and_pragmas.rst,
doc/gnat_rm/the_gnat_library.rst,
doc/gnat_rm/the_implementation_of_standard_i_o.rst,
doc/gnat_ugn/building_executable_programs_with_gnat.rst,
doc/gnat_ugn/gnat_and_program_execution.rst,
doc/gnat_ugn/platform_specific_information.rst: Fix unbalanced
parentheses and brackets.
* sem_prag.adb (pragma Obsolescent): Likewise.
* gnat_rm.texi, gnat_ugn.texi: Regenerate.