Doc suggestion for stdin and .gitingore behavior

[JohnC32]

Using ripgrep 11.0.2 I ran into a hang using ripgrep from GNU Emacs via helm-rg on Windows. Window creates a stdin and ripgrep detects that stdin exists and waits for data, making it look like ripgrep is hung. I was able to easily work around the issue once I saw that I could explicitly specify the directory to search. Having this in the doc may save others confusion. Also having the note about .gitignore's are only respected if .git exists.

The man page intro currently contains:

   ripgrep (rg) recursively searches your current directory for a regex pattern. By default,
   ripgrep will respect your .gitignore and automatically skip hidden files/directories and
   binary files.

Could it be updated to:

   ripgrep (rg) recursively searches your current directory for a regex pattern. By default,
   ripgrep will respect your .gitignore files when a .git directory exists and automatically skip
   hidden files/directories and binary files.

   ripgrep will automatically detect if stdin exists and search stdin for a regex pattern, e.g.
   "ls | rg foo". In some environments, stdin may exist when it shouldn't. To turn off stdin
   detection explicitly specify the directory to search, e.g. "rg foo ./".

It would also be nice to mention why you need a .git directory to have .gitignores but that may be lost in time?

Thanks