Text Editor Pie Menu by Lapineige from here: https://blenderartists.org/t/addon-auto-completion-in-blenders-text-editor/627858/13

TextEditorPieMenu.py

# -*- coding: utf-8 -*-

# ##### BEGIN GPL LICENSE BLOCK #####
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
# ##### END GPL LICENSE BLOCK #####

bl_info = {
    "name": "Text Editor Pie Menu",
    "description": "A Pie Menu for the Text Editor",
    "author": "Lapineige, tintwotin",
    "version": (0, 1, 0),
    "blender": (2, 80, 0),
    "location": "keyboard",
    "warning": "Press Ctrl W to use the pie.",
    "wiki_url": "",
    "category": "Text Editor"
    }

import bpy
from re import search
from bpy.types import Menu


def changeText(self, context):
    bpy.context.space_data.text = bpy.data.texts[bpy.context.scene.tmp_text]

bpy.types.Scene.tmp_text = bpy.props.EnumProperty(items=[(txt.name, txt.name, '', '', bpy.data.texts.find(txt.name)) for txt in bpy.data.texts], update=changeText)


class TEXT_MT_pie(Menu):
    # label is displayed at the center of the pie menu.
    bl_label = "Text Editor Pie"
    bl_idname = "text.text_editor_pie"

    @classmethod
    def poll(cls, context):
        return context.space_data.type == 'TEXT_EDITOR'

    def draw(self, context):
        layout = self.layout

        pie = layout.menu_pie()
        pie.operator('text.unindent')
        pie.operator('text.better_indent', text='Indent')
        pie.prop(context.space_data, 'show_word_wrap', text='Wrap')
        pie.operator('text.run_script')
        pie.operator('text.better_uncomment', text='Uncomment')
        pie.operator('text.better_comment', text='Comment')
        pie.operator('text.select_line')
        pie.menu(menu='text.text_list_menu', text='Choose Text')


class TEXT_MT_list(bpy.types.Menu):
    bl_label = "Text List"
    bl_idname = "text.text_list_menu"

    def draw(self, context):
        layout = self.layout
        layout.props_enum(context.scene, 'tmp_text')


class BetterComment(bpy.types.Operator):
    """  """
    bl_idname = "text.better_comment"
    bl_label = "Better Comment"

    def execute(self, context):
        base = context.space_data.text.current_line.body
        bpy.ops.text.comment()
        if context.space_data.text.current_line.body == base:
            context.space_data.text.current_line.body = '#' + context.space_data.text.current_line.body
        return {'FINISHED'}


class BetterUnComment(bpy.types.Operator):
    """  """
    bl_idname = "text.better_uncomment"
    bl_label = "Better Uncomment"

    def execute(self, context):
        base = context.space_data.text.current_line.body
        bpy.ops.text.uncomment()
        if '#' in base:
            if context.space_data.text.current_line.body == base and search(r'[^#]', base).start() > base.index('#'):
                context.space_data.text.current_line.body = base[search(r'[^#]', base).start():]
        return {'FINISHED'}


class BetterIndent(bpy.types.Operator):
    """  """
    bl_idname = "text.better_indent"
    bl_label = "Better Indent"

    def execute(self, context):
        base = context.space_data.text.current_line.body
        bpy.ops.text.indent()
        if search(r'[^ ]', context.space_data.text.current_line.body).start() == search(r'[^ ]', base).start():
            context.space_data.text.current_line.body = ' '*context.space_data.tab_width + base
        return {'FINISHED'}


addon_keymaps = []
    

def register():
    bpy.utils.register_class(TEXT_MT_pie)
    bpy.utils.register_class(TEXT_MT_list)
    bpy.utils.register_class(BetterComment)
    bpy.utils.register_class(BetterUnComment)
    bpy.utils.register_class(BetterIndent)
    wm = bpy.context.window_manager
    kc = bpy.context.window_manager.keyconfigs.addon
    if wm.keyconfigs.addon:
        
        km = wm.keyconfigs.addon.keymaps.new(name = "Window",space_type='EMPTY', region_type='WINDOW')
 
        kmi = km.keymap_items.new('wm.call_menu_pie', 'W', 'PRESS', ctrl=True)
        kmi.properties.name = TEXT_MT_pie.bl_idname
        addon_keymaps.append((km,kmi))

def unregister():
    bpy.utils.unregister_class(TEXT_MT_pie)
    bpy.utils.unregister_class(TEXT_MT_list)
    bpy.utils.unregister_class(BetterComment)
    bpy.utils.unregister_class(BetterUnComment)
    bpy.utils.unregister_class(BetterIndent)
    wm = bpy.context.window_manager
    kc = wm.keyconfigs.addon
    if kc:
        for km, kmi in addon_keymaps:
            km.keymap_items.remove(kmi)
    addon_keymaps.clear()

if __name__ == "__main__":
    register()

##bpy.ops.wm.call_menu_pie(name=TEXT_MT_pie.bl_idname)