Fix code snippets in docs not passing tests on versions matching their pragmas

docs/contracts/constant-state-variables.rst

@@ -30,7 +30,7 @@ Not all types for constants and immutables are implemented at this time. The onl
 ::
 
     // SPDX-License-Identifier: GPL-3.0
-    pragma solidity >0.7.2;
+    pragma solidity >=0.7.4;
 
     uint constant X = 32**22 + 8;
 

docs/introduction-to-smart-contracts.rst

@@ -83,7 +83,7 @@ registering with a username and password, all you need is an Ethereum keypair.
 ::
 
     // SPDX-License-Identifier: GPL-3.0
-    pragma solidity >0.5.99 <0.8.0;
+    pragma solidity >=0.7.0 <0.8.0;
 
     contract Coin {
         // The keyword "public" makes variables

docs/natspec-format.rst

@@ -49,7 +49,7 @@ The following example shows a contract and a function using all available tags.
 .. code:: Solidity
 
     // SPDX-License-Identifier: GPL-3.0
-    pragma solidity >0.6.10 <0.8.0;
+    pragma solidity >=0.6.12 <0.8.0;
 
     /// @title A simulator for trees
     /// @author Larry A. Gardner

docs/style-guide.rst

@@ -1071,6 +1071,10 @@ No::
 
 and in ``Congress.sol``::
 
+    // SPDX-License-Identifier: GPL-3.0
+    pragma solidity ^0.7.0;
+
+
     import "./owned.sol";
 
 

docs/types/reference-types.rst

@@ -243,7 +243,7 @@ individual elements:
 ::
 
     // SPDX-License-Identifier: GPL-3.0
-    pragma solidity >=0.4.0 <0.8.0;
+    pragma solidity >=0.4.16 <0.8.0;
 
     contract C {
         function f() public pure {
@@ -554,4 +554,4 @@ assigning it to a local variable, as in
 .. note::
     Until Solidity 0.7.0, memory-structs containing members of storage-only types (e.g. mappings)
     were allowed and assignments like ``campaigns[campaignID] = Campaign(beneficiary, goal, 0, 0)``
-    in the example above would work and just silently skip those members.
+    in the example above would work and just silently skip those members.