Fix table spacing in components/lock

Fixes the following diagnostic emitted by `_build/build.php`

```
Malformed table: content "` " appears in the "gap" on row ":ref:`DoctrineDbalPostgreSqlStore <lock-store-dbal-pgsql>`
remote  yes       no       yes"
in file /home/thymos/doc/mydvl/symfony/symfony-docs/components/lock.rst

=========================================================  ======  ========  ======== =======
Store                                                      Scope   Blocking  Expiring Sharing
=========================================================  ======  ========  ======== =======
:ref:`FlockStore <lock-store-flock>`                       local   yes       no       yes
:ref:`MemcachedStore <lock-store-memcached>`               remote  no        yes      no
:ref:`MongoDbStore <lock-store-mongodb>`                   remote  no        yes      no
:ref:`PdoStore <lock-store-pdo>`                           remote  no        yes      no
:ref:`DoctrineDbalStore <lock-store-dbal>`                 remote  no        yes      no
:ref:`PostgreSqlStore <lock-store-pgsql>`                  remote  yes       no       yes
:ref:`DoctrineDbalPostgreSqlStore <lock-store-dbal-pgsql>` remote  yes       no       yes
:ref:`RedisStore <lock-store-redis>`                       remote  no        yes      yes
:ref:`SemaphoreStore <lock-store-semaphore>`               local   yes       no       no
:ref:`ZookeeperStore <lock-store-zookeeper>`               remote  no        no       no
========================================================= ======  ========  ======== =======
```

Author: MarkPedron

components/lock.rst

@@ -350,20 +350,20 @@ Locks are created and managed in ``Stores``, which are classes that implement
 
 The component includes the following built-in store types:
 
-=========================================================  ======  ========  ======== =======
-Store                                                      Scope   Blocking  Expiring Sharing
-=========================================================  ======  ========  ======== =======
-:ref:`FlockStore <lock-store-flock>`                       local   yes       no       yes
-:ref:`MemcachedStore <lock-store-memcached>`               remote  no        yes      no
-:ref:`MongoDbStore <lock-store-mongodb>`                   remote  no        yes      no
-:ref:`PdoStore <lock-store-pdo>`                           remote  no        yes      no
-:ref:`DoctrineDbalStore <lock-store-dbal>`                 remote  no        yes      no
-:ref:`PostgreSqlStore <lock-store-pgsql>`                  remote  yes       no       yes
-:ref:`DoctrineDbalPostgreSqlStore <lock-store-dbal-pgsql>` remote  yes       no       yes
-:ref:`RedisStore <lock-store-redis>`                       remote  no        yes      yes
-:ref:`SemaphoreStore <lock-store-semaphore>`               local   yes       no       no
-:ref:`ZookeeperStore <lock-store-zookeeper>`               remote  no        no       no
-=========================================================  ======  ========  ======== =======
+==========================================================  ======  ========  ======== =======
+Store                                                       Scope   Blocking  Expiring Sharing
+==========================================================  ======  ========  ======== =======
+:ref:`FlockStore <lock-store-flock>`                        local   yes       no       yes
+:ref:`MemcachedStore <lock-store-memcached>`                remote  no        yes      no
+:ref:`MongoDbStore <lock-store-mongodb>`                    remote  no        yes      no
+:ref:`PdoStore <lock-store-pdo>`                            remote  no        yes      no
+:ref:`DoctrineDbalStore <lock-store-dbal>`                  remote  no        yes      no
+:ref:`PostgreSqlStore <lock-store-pgsql>`                   remote  yes       no       yes
+:ref:`DoctrineDbalPostgreSqlStore <lock-store-dbal-pgsql>`  remote  yes       no       yes
+:ref:`RedisStore <lock-store-redis>`                        remote  no        yes      yes
+:ref:`SemaphoreStore <lock-store-semaphore>`                local   yes       no       no
+:ref:`ZookeeperStore <lock-store-zookeeper>`                remote  no        no       no
+==========================================================  ======  ========  ======== =======
 
 .. _lock-store-flock: