docs: YAML: Add `arg_flattening: false` where required

docs/yaml/builtins/meson.yaml

@@ -259,6 +259,7 @@ methods:
 
       This method is replaced by [[meson.get_external_property]].
 
+    arg_flattening: false
     posargs_inherit: meson.get_external_property
     optargs_inherit: meson.get_external_property
 
@@ -269,6 +270,8 @@ methods:
       Returns the given property from a native or cross file.
       The optional fallback_value is returned if the given property is not found.
 
+    arg_flattening: false
+
     posargs:
       propname:
         type: str

docs/yaml/elementary/dict.yml

@@ -30,6 +30,8 @@ methods:
     fallback value given as the second argument. If a single argument
     was given and the key was not found, causes a fatal error
 
+  arg_flattening: false
+
   posargs:
     key:
       type: str

docs/yaml/elementary/list.yml

@@ -10,6 +10,8 @@ methods:
     Returns `true` if the array contains the object
     given as argument, `false` otherwise
 
+  arg_flattening: false
+
   posargs:
     item:
       type: any
@@ -23,6 +25,8 @@ methods:
     bounds returns the `fallback` value *(since 0.38.0)* or, if it is
     not specified, causes a fatal error
 
+  arg_flattening: false
+
   posargs:
     index:
       type: int

docs/yaml/elementary/str.yml

@@ -21,6 +21,8 @@ methods:
     # res now has value 'string: text, number: 1, bool: true'
     ```
 
+  arg_flattening: false
+
   posargs:
     fmt:
       description: |

docs/yaml/functions/environment.yaml

@@ -3,6 +3,8 @@ returns: env
 since: 0.35.0
 description: Returns an empty [[@env]] object.
 
+arg_flattening: false
+
 optargs:
   env:
     type: str | list[str] | dict[str] | dict[list[str]]

docs/yaml/functions/error.yaml

@@ -2,6 +2,8 @@ name: error
 returns: void
 description: Print the argument string and halts the build process.
 
+arg_flattening: false
+
 posargs:
   message:
     type: str

docs/yaml/functions/get_variable.yaml

@@ -8,6 +8,8 @@ description: |
   `res`instead. If a fallback is not specified, then attempting to read
   a non-existing variable will cause a fatal error.
 
+arg_flattening: false
+
 posargs:
   variable_name:
     type: str

docs/yaml/functions/message.yaml

@@ -2,6 +2,8 @@ name: message
 returns: void
 description: This function prints its argument to stdout.
 
+arg_flattening: false
+
 posargs:
   text:
     type: str | int | bool | list[str | int | bool] | dict[str | int | bool]

docs/yaml/functions/set_variable.yaml

@@ -6,6 +6,8 @@ description: |
 
   *(since 0.46.1)* The `value` parameter can be an array type.
 
+arg_flattening: false
+
 posargs:
   variable_name:
     type: str

docs/yaml/functions/summary.yaml

@@ -61,6 +61,8 @@ example: |
                        True
   ```
 
+arg_flattening: false
+
 posargs:
   key_or_dict:
     type: str | dict[str | bool | int | dep | external_program | list[str | bool | int | dep | external_program]]

docs/yaml/functions/warning.yaml

@@ -3,5 +3,7 @@ returns: void
 since: 0.44.0
 description: This function prints its argument to stdout prefixed with WARNING:.
 
+arg_flattening: false
+
 posargs_inherit: message
 varargs_inherit: message

docs/yaml/objects/subproject.yaml

@@ -19,6 +19,8 @@ methods:
     If a fallback is not specified, then attempting to read a non-existing
     variable will cause a fatal error.
 
+  arg_flattening: false
+
   posargs:
     var_name:
       type: str