Add mach_pattern_separator_break_point config option

Configurations.md

@@ -1163,6 +1163,39 @@ match lorem {
 
 See also: [`indent_match_arms`](#indent_match_arms), [`trailing_comma`](#trailing_comma), [`wrap_match_arms`](#wrap_match_arms).
 
+## `match_pattern_separator_break_point`
+
+Put a match sub-patterns' separator (`|`) in front or back.
+
+- **Default value**: `"Back"`
+- **Possible values**: `"Back"`, `"Front"`
+
+#### `"Back"`
+
+```rust
+match m {
+    Variant::Tag |
+    Variant::Tag2 |
+    Variant::Tag3 |
+    Variant::Tag4 |
+    Variant::Tag5 |
+    Variant::Tag6 => {}
+}
+```
+
+#### `Front`
+
+```rust
+match m {
+    Variant::Tag
+    | Variant::Tag2
+    | Variant::Tag3
+    | Variant::Tag4
+    | Variant::Tag5
+    | Variant::Tag6 => {}
+}
+```
+
 ## `max_width`
 
 Maximum width of each line

src/config.rs

@@ -17,7 +17,7 @@
 use std::path::{Path, PathBuf};
 
 use file_lines::FileLines;
-use lists::{ListTactic, SeparatorTactic};
+use lists::{ListTactic, SeparatorPlace, SeparatorTactic};
 
 macro_rules! configuration_option_enum{
     ($e:ident: $( $x:ident ),+ $(,)*) => {
@@ -581,6 +581,8 @@ pub fn get_toml_path(dir: &Path) -> Result<Option<PathBuf>, Error> {
         "Put a trailing comma after a block based match arm (non-block arms are not affected)";
     indent_match_arms: bool, true, "Indent match arms instead of keeping them at the same \
                                     indentation level as the match keyword";
+    match_pattern_separator_break_point: SeparatorPlace, SeparatorPlace::Back,
+        "Put a match sub-patterns' separator in front or back.";
     closure_block_indent_threshold: isize, 7, "How many lines a closure must have before it is \
                                                block indented. -1 means never use block indent.";
     space_before_type_annotation: bool, false,