clang-tidy: merge namespace specifiers

alib2algo/src/automaton/convert/ToRTEStateElimination.cpp

alib2algo/src/automaton/generate/RandomAutomatonFactory.cpp

...lgo/src/automaton/generate/RandomTreeAutomatonFactory.cpp

alib2algo/src/automaton/transform/RHPDAToPDA.cpp

alib2algo/src/grammar/generate/RandomGrammarFactory.cpp

alib2algo/src/regexp/convert/ToAutomatonThompson.cpp

alib2algo/src/regexp/generate/RandomRegExpFactory.cpp

alib2algo/src/string/generate/RandomStringFactory.cpp

alib2algo/src/tree/generate/RandomTreeFactory.cpp

alib2algo_experimental/src/automaton/MinimizeGenerator.cpp

...go_experimental/src/automaton/RandomAutomatonFactory2.cpp

...go_experimental/src/automaton/RandomAutomatonFactory3.cpp

...experimental/src/grammar/parsing/AbsorbTerminalSymbol.cpp

...erimental/src/grammar/parsing/DeterministicLL1Grammar.cpp

...mental/src/grammar/parsing/DeterministicLL1ParseTable.cpp

..._experimental/src/grammar/parsing/ExtractRightContext.cpp

...rimental/src/grammar/parsing/HandleFirstFirstConflict.cpp

...imental/src/grammar/parsing/HandleFirstFollowConflict.cpp

alib2algo_experimental/src/grammar/parsing/LR0Parser.cpp

alib2algo_experimental/src/grammar/parsing/LRParser.cpp