[FR] new TUI features such as regex syntax highlighting

[genivia-inc]

Work in progress TUI additions for upcoming release 4.3.1:

• make Tab navigation to directories and files also work when command line FILE arguments are present (✅ done)
• make CTRL-Y file view work for standard input searched (✅ done)
• make CTRL-Y file view work for files stored in archives by piping a decompressed file to the viewer (✅ done)
• syntax highlight regular expression patterns in the TUI with user-definable colors (✅ done)

Planned for release after Oct 18.

Example regex syntax highlighting in the TUI with the default color scheme:

The user-definable TUI colors are defined in the same way the GREP_COLORS and --colors=COLORS are set with the following new parameters, which are all optional (when not specified the default is used):

param	result
qp=	TUI prompt
qe=	TUI errors
qr=	TUI regex
qm=	TUI regex meta characters
ql=	TUI regex lists and literals
qb=	TUI regex braces

[genivia-inc]

Released v4.3.1