Remove deprecated expr_string module

The expr_string module and its associated types (ExprString, exprQuote,
isExprString, useExprString) have been deprecated in favor of the eval
module's rawString functionality. This commit removes all deprecated code
and updates dependent files to use the new API.

Changes:
- Remove helper/expr_string.ts and helper/expr_string_test.ts
- Update helper/keymap.ts to remove ExprString type support
- Update eval/stringify.ts to remove isExprString checks
- Remove related test cases from affected test files
- Remove exports from helper/mod.ts and deno.jsonc

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: lambdalisue

deno.jsonc

@@ -19,7 +19,6 @@
     "./helper": "./helper/mod.ts",
     "./helper/echo": "./helper/echo.ts",
     "./helper/execute": "./helper/execute.ts",
-    "./helper/expr_string": "./helper/expr_string.ts",
     "./helper/getbufinfo": "./helper/getbufinfo.ts",
     "./helper/input": "./helper/input.ts",
     "./helper/keymap": "./helper/keymap.ts",
@@ -81,7 +80,6 @@
     "jsr:@denops/std/helper": "./helper/mod.ts",
     "jsr:@denops/std/helper/echo": "./helper/echo.ts",
     "jsr:@denops/std/helper/execute": "./helper/execute.ts",
-    "jsr:@denops/std/helper/expr_string": "./helper/expr_string.ts",
     "jsr:@denops/std/helper/input": "./helper/input.ts",
     "jsr:@denops/std/helper/keymap": "./helper/keymap.ts",
     "jsr:@denops/std/helper/load": "./helper/load.ts",

eval/stringify.ts

@@ -15,7 +15,6 @@ import { isRecord } from "@core/unknownutil/is/record";
 import { isString } from "@core/unknownutil/is/string";
 import { isSymbol } from "@core/unknownutil/is/symbol";
 import { isUndefined } from "@core/unknownutil/is/undefined";
-import { isExprString } from "../helper/expr_string.ts";
 import {
   isVimEvaluatable,
   type VimEvaluatable,
@@ -80,17 +79,11 @@ export function stringify(value: unknown): string {
     if (isVimEvaluatable(value)) {
       return toVimExpression(value);
     }
-    if (isExprString(value)) {
-      return `"${value.replaceAll('"', '\\"')}"`;
-    }
     if (isCustomJsonable(value)) {
       value = value.toJSON(key);
       if (isVimEvaluatable(value)) {
         return toVimExpression(value);
       }
-      if (isExprString(value)) {
-        return `"${value.replaceAll('"', '\\"')}"`;
-      }
     }
     if (isNullish(value) || isFunction(value) || isSymbol(value)) {
       return "v:null";

eval/stringify_test.ts

@@ -4,7 +4,6 @@ import { test } from "@denops/test";
 import { expr } from "./expression.ts";
 import { rawString } from "./string.ts";
 import { type VimEvaluatable, vimExpressionOf } from "./vim_evaluatable.ts";
-import { exprQuote } from "../helper/expr_string.ts";
 
 import { stringify } from "./stringify.ts";
 
@@ -88,10 +87,6 @@ Deno.test("stringify()", async (t) => {
     const actual = stringify(rawString`\<Cmd>call Foo("bar")\<CR>`);
     assertEquals(actual, '"\\<Cmd>call Foo(\\"bar\\")\\<CR>"');
   });
-  await t.step("stringify ExprString to Vim's expr-string", () => {
-    const actual = stringify(exprQuote`\<Cmd>call Foo("bar")\<CR>`);
-    assertEquals(actual, '"\\<Cmd>call Foo(\\"bar\\")\\<CR>"');
-  });
   await t.step("stringify array to Vim's list", () => {
     const actual = stringify(["foo", 42, null, undefined]);
     assertEquals(actual, "['foo',42,v:null,v:null]");
@@ -173,13 +168,6 @@ Deno.test("stringify()", async (t) => {
     const actual = stringify(x);
     assertEquals(actual, '"\\<Cmd>call Foo(\\"bar\\")\\<CR>"');
   });
-  await t.step("stringify ExprString that returns from `toJSON`", () => {
-    const x = {
-      toJSON: () => exprQuote`\<Cmd>call Foo("bar")\<CR>`,
-    };
-    const actual = stringify(x);
-    assertEquals(actual, '"\\<Cmd>call Foo(\\"bar\\")\\<CR>"');
-  });
   await t.step("stringify object that has `toJSON` method", () => {
     const actual = stringify({
       foo: 42,