docs: fix duplicated words

book/custom_completions.md

@@ -109,7 +109,7 @@ module commands {
 }
 ```
 
-In this module, only the the custom command `my-command` is exported. The `animals` completion is not exported. This allows users of this module to call the command, and even use the custom completion logic, without having access to the completion command itself. This results in a cleaner and more maintainable API.
+In this module, only the custom command `my-command` is exported. The `animals` completion is not exported. This allows users of this module to call the command, and even use the custom completion logic, without having access to the completion command itself. This results in a cleaner and more maintainable API.
 
 ::: tip
 Completers are attached to custom commands using `@` at parse time. This means that, in order for a change to the completion command to take effect, the public custom command must be reparsed as well. Importing a module satisfies both of these requirements at the same time with a single `use` statement.

book/dataframes.md

@@ -863,7 +863,7 @@ As expected, the command returns a new dataframe that can be used to do more
 queries.
 
 Continuing with our exploration of `Series`, the next thing that we can do is
-to only get the unique unique values from a series, like this
+to only get the unique values from a series, like this
 
 ```nu
 $df_1 | polars get first | polars unique
@@ -1143,7 +1143,7 @@ This list may be outdated. To get the up-to-date command list, see [Dataframe](/
 | polars implode         | expression            | Aggregates a group to a Series.                                                                  |                         |
 | polars into-df         | any                   | Converts a list, table or record into a dataframe.                                               |                         |
 | polars into-lazy       | any                   | Converts a dataframe into a lazy dataframe.                                                      |                         |
-| polars into-nu         | expression, dataframe | Converts a dataframe or an expression into into nushell value for access and exploration.        |                         |
+| polars into-nu         | expression, dataframe | Converts a dataframe or an expression into nushell value for access and exploration.        |                         |
 | polars is-duplicated   | dataframe             | Creates mask indicating duplicated values.                                                       |                         |
 | polars is-in           | expression, dataframe | Creates an is-in expression or checks to see if the elements are contained in the right series   | in                      |
 | polars is-not-null     | expression, dataframe | Creates mask where value is not null.                                                            |                         |

lang-guide/chapters/types/type_signatures.md

@@ -78,4 +78,4 @@ binding will be `bool` and its value will be `true` if the flag is present
 and `false` if not present.
 
 You cannot use the `bool` type as a flag annotation as that is the same
-as the the existence or not of the occurrence of the flag.
+as the existence or not of the occurrence of the flag.