update README, closes #1116

Author: ikitommi

CHANGELOG.md

@@ -14,6 +14,10 @@ We use [Break Versioning][breakver]. The version numbers follow a `<major>.<mino
 
 Malli is in well matured [alpha](README.md#alpha).
 
+## 
+
+* Docs: elaborate optional-keys and required-keys [#1117](https://github.com/metosin/malli/pull/1117)
+
 ## 0.17.0 (2024-12-08)
 
 * Don't output `:definitions nil` in swagger. [#1134](https://github.com/metosin/malli/issues/1134)

README.md

@@ -331,6 +331,8 @@ Most core-predicates are mapped to Schemas:
 ; => true
 ```
 
+*NOTE*: Predicate Schemas do not cover any schema properties, e.g. `string?` can be modified with properties like `:min` and `:max`. If you want to use the schema properties, use real schema types instead, e.g. `:string` over `string?`.
+
 See [the full list of default schemas](#schema-registry).
 
 ## Enumeration schemas
@@ -3476,6 +3478,8 @@ The transformation engine is smart enough to just transform parts of the schema
 
 Contains both function values and unqualified symbol representations for all relevant core predicates. Having both representations enables reading forms from both code (function values) and EDN-files (symbols): `any?`, `some?`, `number?`, `integer?`, `int?`, `pos-int?`, `neg-int?`, `nat-int?`, `pos?`, `neg?`, `float?`, `double?`, `boolean?`, `string?`, `ident?`, `simple-ident?`, `qualified-ident?`, `keyword?`, `simple-keyword?`, `qualified-keyword?`, `symbol?`, `simple-symbol?`, `qualified-symbol?`, `uuid?`, `uri?`, `decimal?`, `inst?`, `seqable?`, `indexed?`, `map?`, `vector?`, `list?`, `seq?`, `char?`, `set?`, `nil?`, `false?`, `true?`, `zero?`, `rational?`, `coll?`, `empty?`, `associative?`, `sequential?`, `ratio?`, `bytes?`, `ifn?` and `fn?`.
 
+*NOTE*: Predicate Schemas do not cover any schema properties, e.g. `string?` can be modified with properties like `:min` and `:max`. If you want to use the schema properties, use real schema types instead, e.g. `:string` over `string?`.
+
 ### `malli.core/class-schemas`
 
 Class-based schemas, contains `java.util.regex.Pattern` & `js/RegExp`.