chore(docs): add missing pub to return value of main function

docs/docs/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.10.5/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.17.0/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.19.0/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.19.1/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.19.2/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.19.3/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.19.4/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.6.0/language_concepts/07_mutability.md

@@ -39,7 +39,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.7.1/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3

docs/versioned_docs/version-v0.9.0/language_concepts/07_mutability.md

@@ -37,7 +37,7 @@ Note that mutability in noir is local and everything is passed by value, so if a
 mutates its parameters then the parent function will keep the old value of the parameters.
 
 ```rust
-fn main() -> Field {
+fn main() -> pub Field {
     let x = 3;
     helper(x);
     x // x is still 3