message: Fixed typos in nGQL.md
diff: ### Common BNF
  <simple\_type> ::= **vid** | **integer** | **double** | **float** | **bool** | **string** | **path** | **timestamp** | **year** | **month** | **date** | **datetime**
  -<composit_type> ::=
  +<composite_type> ::=
  <type\> ::= <simple_type> | <composite\_type>
  <underscore\_label> ::= ("\_")* <label\>
  -<field\_name> ::= <lable\>
  +<field\_name> ::= <label\>
  <field\_def\_list> ::= <field\_def> (, <field\_def>)\*
  @@ -177,7 +177,7 @@ Navigate from given vertices to their neighbors according to the given condition
  [<span style="color:blue">**WHERE**</span> <filter\_list>]
  [<span style="color:blue">**YIELD**</span> <field\_list>]
  -<steps\_decl> ::= **integer** | **integer** <span style="color:blue">**TO**</span> **integer** | <span style="color:blue">**UPTO**</span> **interger** <br>
  +<steps\_decl> ::= **integer** | **integer** <span style="color:blue">**TO**</span> **integer** | <span style="color:blue">**UPTO**</span> **integer** <br>
  <data\_set\_decl> ::= [data\_set] [[<span style="color:blue">**AS**</span>] <label\>]<br/>
  <data\_set> ::= **vid** | <vid\_list> | <tuple\_list\_decl> | <var\><br/>
  <edge\_type\_decl> ::= <edge\_type\_list> [<span style="color:blue">**AS**</span> <label\>]
  @@ -228,7 +228,7 @@ Following statements looks for vertices or edges that match certain conditions
  <span style="color:blue">**WHERE**</span> <filter\_list>
  [<span style="color:blue">**YIELD**</span> <field\_list>]
  -#### Pattern mactch
  +#### Pattern match
  The following statement does a pattern match, and can return tuple list or paths
  <span style="color:blue">**MATCH**</span>
  @@ -243,7 +243,7 @@ It's common to refer a property in the statement, such as in <span style="color:
  <property_ref> ::= <object\> "." <prop\_name> <br>
  <object\> ::= <alias\_name> | <alias\_with\_tag> | <var\> <br>
  <alias\_name> ::= <label\> <br>
  -<alias\_wiht\_tag> ::= <alias\_name> '[' <tag\_name> "]" <br>
  +<alias\_with\_tag> ::= <alias\_name> '[' <tag\_name> "]" <br>
  <var\> always starts with "$". There are two special variables: $_ and $$.
  