searcher: move "max matches" from printer to searcher

This is a bit of a brutal change, but I believe is necessary in order to
fix a bug in how we handle the "max matches" limit in multi-line mode
while simultaneously handling context lines correctly.

The main problem here is that "max matches" refers to the shorter of
"one match per line" or "a single match." In typical grep, matches
*can't* span multiple lines, so there's never a difference. But in
multi-line mode, they can. So match counts necessarily must be handled
differently for multi-line mode.

The printer was previously responsible for this. But for $reasons, the
printer is fundamentally not in charge of how matches are found and
reported.

See my comments in #3094 for even more context.

This is a breaking change for `grep-printer`.

Fixes #3076, Closes #3094

crates/core/flags/defs.rs

@@ -3877,6 +3877,10 @@ impl Flag for MaxCount {
         r"
 Limit the number of matching lines per file searched to \fINUM\fP.
 .sp
+When \flag{multiline} is used, a single match that spans multiple lines is only
+counted once for the purposes of this limit. Multiple matches in a single line
+are counted only once, as they would be in non-multiline mode.
+.sp
 Note that \fB0\fP is a legal value but not likely to be useful. When used,
 ripgrep won't search anything.
 "

crates/core/flags/hiargs.rs

@@ -617,7 +617,6 @@ impl HiArgs {
             .hyperlink(self.hyperlink_config.clone())
             .max_columns_preview(self.max_columns_preview)
             .max_columns(self.max_columns)
-            .max_matches(self.max_count)
             .only_matching(self.only_matching)
             .path(self.with_filename)
             .path_terminator(self.path_terminator.clone())
@@ -719,6 +718,7 @@ impl HiArgs {
         };
         let mut builder = grep::searcher::SearcherBuilder::new();
         builder
+            .max_matches(self.max_count)
             .line_terminator(line_term)
             .invert_match(self.invert_match)
             .line_number(self.line_number)