Want ability to set placeholder text separately from label in fields

Currently blocks contain only a label field, which renders to the field label and placeholder text. Ideally I’d like to set the placeholder text separately.

For instance, say I have an email field. I’d want it to be:

label: Email placeholder: [e-mail]

This helps guide the user on the sort of content they need to enter into the field.

[zeroepix]

I’ve not done a PR before, nor worked with rst doc but I’ve given it a go here: forked repo / pull request #6309

Let me know if I should put it somewhere else or make any changes.

[zeroepix]

For anyone ending up here trying to figure out how to add a simple placeholder to a field in Wagtail’s admin view, and end up scratching their heads, it’s actually quite easy. Say you’ve made a soldier model that content creators will use, and you want to put a placeholder in the field, just do something like this:

# models.py
from django import forms
from django.db import models
from wagtail.admin import widgets # to use wagtails special datetime widget

class Soldier(models.Model)::
    name = models.CharField(max_length=48)
    date_of_birth = models.DateField(null=True, default=None, blank=True)
    serial_number = models.DecimalField(null=True, default=None, blank=True)
    
    panels = [
        MultiFieldPanel(
            [
                FieldRowPanel(
                    children = (
                        FieldPanel('name', widget=forms.TextInput(attrs={'placeholder': 'Enter Full Name'})),
                        FieldPanel('date_of_birth', widget=widgets.AdminDateInput(attrs={'placeholder':'dd-mm-yyyy'})),
                        FieldPanel('height', widget=forms.NumberInput(attrs={'placeholder': 'in cm only'})),
                    )
                ),
            ],
            heading = "Personal Information",
            classname = "collapsible"

You can select from the widgets here, plus whatever you find in wagtail\admin\widgets.py