bin/repl: match as whole-word text (like SQL identifier): documented that this is a generalization of lib/sql_gen.py map_expr() to work on entire source files

bin/repl, lib/sql_gen.py Expression transforming: documented that this can also be done in Postgres with expression substitution (wiki.vegpath.org/Postgres_queries#expression-substitution)

bin/make_analytical_db: removed remake_diff_tables() because this is now done for each datasource in inputs/input.Makefile

bin/make_analytical_db: removed no longer needed "${public}_validations" schema qualifier, now that it is in the search_path

fix: bin/vegbien_dest: added public_validations

fix: bin/repl: text mode (whether all patterns are plain text) should default to on, not off, if matching entire cells in a spreadsheet

fix: bin/repl: don't consider uppercase SQL keywords to indicate that a word is in a sentence

bugfix: bin/repl: only use excluded_prefix_re/excluded_suffix_re in text mode (used in renaming columns in SQL scripts), to prevent the special coding for column renames from also affecting regular regexp/word replacements

bugfix: bin/repl: text mode: also don't match if it's part of a '-'-separated identifier

bugfix: bin/repl: text mode: also don't match if it's a word in a sentence