Add initial support for custom sniffing

_reformat-common.bash

@@ -68,6 +68,21 @@ function resolve_symlink() {
     echo "$out"
 }
 
+function custom_sniff() {
+    file="$1"
+
+    pr=$(project_root "$file")
+
+    if [[ -f "$pr/.would-reformat/custom-sniffer" ]]; then
+        custom=$("$pr/.would-reformat/custom-sniffer" "$1")
+        ret="$?"
+
+        echo "$custom"
+
+        return 0
+    fi
+}
+
 function custom_formatter() {
     root="$1"
     file_type="$2"
@@ -88,6 +103,12 @@ function sniff_file_type() {
     ff=$1
     shift
 
+    maybe_custom=$(custom_sniff "$ff")
+    if [[ "$maybe_custom" != "" ]]; then
+        echo "$maybe_custom"
+        return 0
+    fi
+
     file_type=
 
     if [[ $ff == *.py ]]; then
@@ -118,6 +139,8 @@ function sniff_file_type() {
         file_type="golang"
     elif [[ $ff = *.dart ]]; then
         file_type="dart"
+    elif [[ $ff = *.pl ]]; then
+        file_type="perl"
     fi
 
     echo $file_type