fix!: no mixed receiver types (#23)

## Description

Currently, `bucket` and `Table` have mixed receiver types: some are pointer receviers, and others are value receivers.

As per the Go Wiki, [you can have value and pointer receivers, just don't mix them](https://go.dev/doc/faq#methods_on_values_or_pointers).

## Changes

- Replace all value receivers in `bucket` and `Table` with pointer receivers.

### Design Decisions

This decision was made due to the advice on the Go wiki.

## Checklist

- [x] Tests pass
- [x] Docs updated

Reviewed-on: #23
Co-authored-by: M.V. Hutz <git@maximhutz.me>
Co-committed-by: M.V. Hutz <git@maximhutz.me>

table.go

@@ -97,7 +97,7 @@ func (t *Table[K, V]) shrink() error {
 
 // Get fetches the value for a key in the [Table]. Matches the comma-ok pattern
 // of a builtin map; see [Table.Find] for plain indexing.
-func (t Table[K, V]) Get(key K) (value V, ok bool) {
+func (t *Table[K, V]) Get(key K) (value V, ok bool) {
 	if item, ok := t.tableA.get(key); ok {
 		return item, true
 	}
@@ -111,13 +111,13 @@ func (t Table[K, V]) Get(key K) (value V, ok bool) {
 
 // Find fetches the value of a key. Matches direct indexing of a builtin map;
 // see [Table.Get] for a comma-ok pattern.
-func (t Table[K, V]) Find(key K) (value V) {
+func (t *Table[K, V]) Find(key K) (value V) {
 	value, _ = t.Get(key)
 	return
 }
 
 // Has returns true if a key has a value in the table.
-func (t Table[K, V]) Has(key K) (exists bool) {
+func (t *Table[K, V]) Has(key K) (exists bool) {
 	_, exists = t.Get(key)
 	return
 }