add precision about static arrays and fix functions' names

docs/design-documents/hal/0002-pinmap-extension.md

@@ -44,11 +44,11 @@ It is proposed to introduce the following elements :
       PINMAP_FORM_FACTOR_MTB,
   } pinmap_form_factor_t;
 
-  /// returns an NC terminated array of pins.
+  /// returns a static NC terminated array of pins.
   const PinName *pinmap_form_factor_pins(pinmap_form_factor_t form_factor);
-  /// returns an NC terminated array of pins.
+  /// returns a static NC terminated array of pins.
   const PinName *pinmap_restricted_pins();
-  /// returns a null (\0) terminated character array.
+  /// returns a null (\0) terminated static character array representing the name of the pin.
   const char *pinmap_pin_to_string(PinName pin);
   ```
 - These generic function make use of the existing API to answer requirements 1, 2 and 6.
@@ -59,20 +59,20 @@ It is proposed to introduce the following elements :
   /// Returns a pin from ((whitelist ∩ map) − blacklist).
   /// Typically, whitelist will be the form factor list of pins.
   /// The blacklist may be a list of pins already visited and/or tied to another peripheral.
-  PinName pinmap_find_peripheral_pins(const PinMap *map, const PinName *whitelist,
+  PinName pinmap_find_peripheral_pin(const PinMap *map, const PinName *whitelist,
                                       const PinName *blacklist, int per);
 
   /// Verifies that `pin` is in `list`.
   bool pinlist_has_pin(const PinName *list, PinName pin);
 
-  /// Applies pinmap_find_peripheral_pins to each map in maps ensuring a pin will not be used twice.
+  /// Applies pinmap_find_peripheral_pin to each map in maps ensuring a pin will not be used twice.
   /// @param[in]  maps      A list of pinmap.
   /// @param[in]  count     Number of elements of maps and pins.
   /// @param[in]  whitelist An NC terminated list of pins.
   /// @param[in]  blacklist An NC terminated list of pins.
   /// @param[in]  per       A peripheral name.
   /// @param[out] pins      An array of PinName where the result is stored.
-  bool pinmap_find_peripheral_bus(const PinMap const **maps,
+  bool pinmap_find_peripheral_pins(const PinMap const **maps,
                                    uint32_t count,
                                    const PinName *whitelist,
                                    const PinName *blacklist,