DOC: added hyper links to new sections

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

doc/FEATURE_SET.md

@@ -7,15 +7,18 @@
    4. [eNB PDCP Layer](#enb-pdcp-layer)
    5. [eNB RRC Layer](#enb-rrc-layer)
    6. [eNB X2AP](#enb-x2ap)
-   7. [eNB Advanced Features](#enb-advanced-features)
-2. [OpenAirInterface UE Feature Set](#openairinterface-ue-feature-set)
+   7. [eNB/MCE M2AP](#enbmce-m2ap)
+   8. [MCE/MME M3AP](#mcemme-m3ap)
+   9. [eNB Advanced Features](#enb-advanced-features)
+2. [OpenAirInterface Functional Split](#openairinterface-functional-split)
+3. [OpenAirInterface UE Feature Set](#openairinterface-ue-feature-set)
    1.  [LTE UE PHY Layer](#lte-ue-phy-layer)
    2.  [LTE UE MAC Layer](#lte-ue-mac-layer)
    3.  [LTE UE RLC Layer](#lte-ue-rlc-layer)
    4.  [LTE UE PDCP Layer](#lte-ue-pdcp-layer)
    5.  [LTE UE RRC Layer](#lte-ue-rrc-layer)
-3. [OpenAirInterface Functional Split](#openairinterface-functional-split)
-4. [OpenAirInterface 5G-NR Feature Set](#openairinterface-5g-nr-feature-set)
+4. [OpenAirInterface Functional Split](#openairinterface-functional-split)
+5. [OpenAirInterface 5G-NR Feature Set](#openairinterface-5g-nr-feature-set)
    1. [General Parameters](#general-parameters)
    2. [gNB Features](#gnb-features)
       1. [gNB Physical Layer](#gnb-phy-layer)
@@ -149,6 +152,7 @@ The X2AP layer is based on **3GPP 36.423** v14.6.0 and implements the following
  - X2-U interface implemented
 
 ## eNB/MCE M2AP ##
+
 The M2AP layer is based on **3GPP 36.443** v14.0.1:
  - M2 Setup Request
  - M2 Setup Response 
@@ -159,6 +163,7 @@ The M2AP layer is based on **3GPP 36.443** v14.0.1:
  - M2 Session Start Response
 
 ## MCE/MME M3AP ##
+
 The M3AP layer is based on **3GPP 36.444** v14.0.1:
  - M3 Setup Request
  - M3 Setup Response