[pandas-vet] Remove pandas-df-variable-name (PD901) (#19223)

## Summary
closes #7710 

## Test Plan

It is is removal so i don't think we have to add tests otherwise i have
followed test plan mentioned in contributing.md

---------

Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>

crates/ruff_linter/src/codes.rs

@@ -773,7 +773,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (PandasVet, "013") => (RuleGroup::Stable, rules::pandas_vet::rules::PandasUseOfDotStack),
         (PandasVet, "015") => (RuleGroup::Stable, rules::pandas_vet::rules::PandasUseOfPdMerge),
         (PandasVet, "101") => (RuleGroup::Stable, rules::pandas_vet::rules::PandasNuniqueConstantSeriesCheck),
-        (PandasVet, "901") => (RuleGroup::Deprecated, rules::pandas_vet::rules::PandasDfVariableName),
+        (PandasVet, "901") => (RuleGroup::Removed, rules::pandas_vet::rules::PandasDfVariableName),
 
         // flake8-errmsg
         (Flake8ErrMsg, "101") => (RuleGroup::Stable, rules::flake8_errmsg::rules::RawStringInException),

crates/ruff_linter/src/rules/pandas_vet/rules/assignment_to_df.rs

@@ -4,9 +4,9 @@ use ruff_text_size::Ranged;
 
 use crate::{Violation, checkers::ast::Checker};
 
-/// ## Deprecated
+/// ## Removed
 ///
-/// This rule has been deprecated as it's highly opinionated and overly strict in most cases.
+/// This rule has been removed as it's highly opinionated and overly strict in most cases.
 ///
 /// ## What it does
 /// Checks for assignments to the variable `df`.

ruff.schema.json

@@ -3557,9 +3557,6 @@
         "PD1",
         "PD10",
         "PD101",
-        "PD9",
-        "PD90",
-        "PD901",
         "PERF",
         "PERF1",
         "PERF10",