pgsql: Improve reporting of run-time-detected indeterminate-collation e

Improve reporting of run-time-detected indeterminate-collation errors.

pg_newlocale_from_collation does not have enough context to give an error
message that's even a little bit useful, so move the responsibility for
complaining up to its callers. Also, reword ERRCODE_INDETERMINATE_COLLATION
error messages in a less jargony, more message-style-guide-compliant
fashion.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/6e197cb2e537880f36828a6c55d0f6df5bf7daa8

Modified Files
--------------
src/backend/commands/collationcmds.c | 2 +-
src/backend/commands/indexcmds.c | 2 +-
src/backend/commands/view.c | 2 +-
src/backend/utils/adt/formatting.c | 78 ++++++++++++++++++++++
src/backend/utils/adt/pg_locale.c | 14 +---
src/backend/utils/adt/varlena.c | 13 ++++
src/test/regress/expected/collate.linux.utf8.out | 6 +-
src/test/regress/expected/collate.out | 6 +-
8 files changed, 105 insertions(+), 18 deletions(-)