Support "and -e" mode

[mqudsi]

Currently --expression/-e can be specified multiple times to specify additional expressions that will result in a line being included in the results. When searching for words containing EXPR1, EXPR2, and EXPR3, it is simple enough to type in -e EXPR1.*EXPR2.*EXPR3 as the pattern. However, if the order of the expression is not important and may vary, it would be necessary to invoke -e EXPR1.*EXPR2.*EXPR3 -e EXPR1.*EXPR3.*EXPR2 -e EXPR2.*EXPR1.*EXPR3 -e EXPR2.*EXPR3.*EXPR1 -e EXPR3.*EXPR1.*EXPR2 -e EXPR3.*EXPR2.*EXPR1.

I'm curious whether you would be open to rg supporting some means of combining patterns/expressions via AND syntax instead of the current OR syntax when given multiple -e statements.

[BurntSushi]

I'd rather track this in one ticket. I modified the title of #875 to encompass the broader story.

I'd be unlikely to do one and not the other. Namely, if we buy into one, then we might as well buy into both.