Cellular: Remove non-API folders from Doxygen

Cellular: Update cellular documentation

Fix NetworkInterface grouping

Doxygen corrections to: ...

- DTLSSocket.h
- TLSSocket.h
- TLSSocketWrapper.h

Fix netsocket Doxygen group

Merge pull request #9418 from naveenkaje/build_api_spell_fix ...

tools: build_api: remove redundant initialization and fix spelling

Merge pull request #9377 from offirko/offir_general_block_device_test ...

test: general_block_device fix to always erase prior the first program

Merge pull request #9344 from Pharap/fix-attach-function ...

Fix bug in templated attach function

Merge pull request #9406 from geky/littlefs-validate-all-dirs ...

Extended mount to check all metadata-pairs

Merge pull request #9407 from offirko/offir_direct_access_handle_default_config ...

DirectAccess DeviceKey: add support for default storage type

Merge pull request #9385 from kapi90/smsc9220_fix ...

Fixes typos in SMSC9220 Ethernet driver

Merge pull request #9386 from jeromecoutant/PR_SDJSON ...

SD default configuration for ST boards is already defined in TARGET_STM

Merge pull request #9403 from ARMmbed/AnotherButler-patch-1 ...

Clarify addition to CONFIGURATION.md

Merge pull request #9380 from kyliuxing/master ...

UNO_91H: open hal lib source

Merge pull request #9376 from michalpasztamobica/tcpsocket_greentea ...

TCP/UDP greentea tests refactoring and cleanup

Merge pull request #9366 from VeijoPesonen/bugfix-esp8266_verify_rcvd_data_len ...

ESP8266: add an error check for data overflow from modem side

Merge pull request #9339 from costanic/fix_oob ...

Fix Out-Of-Band (OOB) data generation for BLE OOB pairing

Merge pull request #9335 from naveenkaje/fix_thred_mle_warning ...

thread_mle_message_handler: fix build warning

Merge pull request #9333 from offirko/offir_doxygen ...

Minor Doxygen fixes for BufferedBlockDevice and iBeacon

Merge pull request #9316 from bentcooke/add_flash_MAX32620FTHR ...

Add FLASH support to TARGET_MAX32620C and brd targets

Merge pull request #9257 from jeromecoutant/PR_FLASHIAP_TIMING ...

FLASHIAP test: skip test if test region overlaps code

tools: build_api: remove redundant initialization and fix spelling

Extended mount to check all metadata-pairs ...

The most common issue with using littlefs in mbed-os is when users
change from littlefs->FAT->littlefs (or with MBR or similar). When this
corrupts the superblock, littlefs tries to fall back to the backup
superblock. However, at this point in the time the old superblock may be
very out-of-date and pointing to an incorrect filesystem.

There's no complete solution to a malicious modification of the
filesystem (short of checking all metadata+data, a very expensive
operation), but we can at least expand our validation to all of the
metadata for the filesystem. This at least catches the common issues
with changing between different filesystems.

DirectAccess DeviceKey added support for default storage type

Merge pull request #8887 from deepikabhavnani/uVision_fix ...

Adding debugger awarness with Keil MDK

Merge pull request #9405 from cmonr/fix-doxy ...

Travis: Fix doxy-spellcheck job

Merge pull request #9096 from pan-/fix-enforce-size-limits ...

BLE: Enforce advertising data payload limits

Merge pull request #9331 from VeijoPesonen/bugfix-esp8266_udp_prevent_would_block ...

ESP8266: prevent WOULD BLOCK from TX if UDP

Merge pull request #9297 from bridadan/fix_os2_tests_uarm ...

uARM targets now build in correct ARM_MICRO directory

Merge pull request #9280 from deepikabhavnani/refactor_a ...

Sleep manager implements all the API's in platform file