Add backtick string literals and formatter support

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/docs/LyngDocumentationProvider.kt

@@ -310,7 +310,7 @@ class LyngDocumentationProvider : AbstractDocumentationProvider() {
                 // Try literal and call-based receiver inference around the dot
                 val i = TextCtx.prevNonWs(text, dotPos - 1)
                 val className: String? = when {
-                    i >= 0 && text[i] == '"' -> "String"
+                    i >= 0 && (text[i] == '"' || text[i] == '`') -> "String"
                     i >= 0 && text[i] == ']' -> "List"
                     i >= 0 && text[i] == '}' -> "Dict"
                     i >= 0 && text[i] == ')' -> {

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/format/LyngPreFormatProcessor.kt

@@ -24,6 +24,7 @@ import com.intellij.psi.codeStyle.CodeStyleManager
 import com.intellij.psi.impl.source.codeStyle.PreFormatProcessor
 import net.sergeych.lyng.format.LyngFormatConfig
 import net.sergeych.lyng.format.LyngFormatter
+import net.sergeych.lyng.format.LyngStringDelimiterPolicy
 import net.sergeych.lyng.idea.LyngLanguage
 
 /**
@@ -170,6 +171,7 @@ class LyngPreFormatProcessor : PreFormatProcessor {
                 continuationIndentSize = options.CONTINUATION_INDENT_SIZE.coerceAtLeast(options.INDENT_SIZE.coerceAtLeast(1)),
                 applySpacing = true,
                 applyWrapping = false,
+                stringDelimiterPolicy = LyngStringDelimiterPolicy.PreferFewerEscapes,
             )
             val r = if (runFullFileIndent) currentLocalRange() else workingRangeLocal.intersection(currentLocalRange()) ?: currentLocalRange()
             val text = doc.getText(r)
@@ -189,6 +191,7 @@ class LyngPreFormatProcessor : PreFormatProcessor {
                 continuationIndentSize = options.CONTINUATION_INDENT_SIZE.coerceAtLeast(options.INDENT_SIZE.coerceAtLeast(1)),
                 applySpacing = settings.enableSpacing,
                 applyWrapping = true,
+                stringDelimiterPolicy = LyngStringDelimiterPolicy.PreferFewerEscapes,
             )
             val r = if (runFullFileIndent) currentLocalRange() else workingRangeLocal.intersection(currentLocalRange()) ?: currentLocalRange()
             val text = doc.getText(r)

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/highlight/LyngLexer.kt

@@ -101,8 +101,8 @@ class LyngLexer : LexerBase() {
             return
         }
 
-        // String "..." or '...' with simple escape handling
-        if (ch == '"' || ch == '\'') {
+        // String "...", `...`, or '...' with simple escape handling
+        if (ch == '"' || ch == '\'' || ch == '`') {
             val quote = ch
             i++
             while (i < endOffset) {

lyng-idea/src/test/kotlin/net/sergeych/lyng/idea/highlight/LyngLexerBacktickStringTest.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2026 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package net.sergeych.lyng.idea.highlight
+
+import org.junit.Assert.assertArrayEquals
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class LyngLexerBacktickStringTest {
+
+    @Test
+    fun backtickStringGetsStringTokenAndColor() {
+        val lexer = LyngLexer()
+        val source = """val json = `{"name":"lyng","doc":"use \`quotes\`"}`"""
+        lexer.start(source, 0, source.length, 0)
+
+        val tokens = mutableListOf<Pair<String, String>>()
+        while (lexer.tokenType != null) {
+            val tokenText = source.substring(lexer.tokenStart, lexer.tokenEnd)
+            tokens += lexer.tokenType.toString() to tokenText
+            lexer.advance()
+        }
+
+        assertEquals(
+            listOf(
+                "KEYWORD" to "val",
+                "WHITESPACE" to " ",
+                "IDENTIFIER" to "json",
+                "WHITESPACE" to " ",
+                "PUNCT" to "=",
+                "WHITESPACE" to " ",
+                "STRING" to "`{\"name\":\"lyng\",\"doc\":\"use \\`quotes\\`\"}`"
+            ),
+            tokens
+        )
+
+        val highlighter = LyngSyntaxHighlighter()
+        assertArrayEquals(
+            arrayOf(LyngHighlighterColors.STRING),
+            highlighter.getTokenHighlights(LyngTokenTypes.STRING)
+        )
+    }
+}