docs: documentation for GEOHASH

docs/src/content/docs/commands/GEOHASH.md

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+---
+title: GEOHASH
+description: The GEOHASH command in DiceDB returns the Geohash representation of specified members stored in a geospatial dataset under a specified key. This allows efficient encoding and querying of geographic points.
+---
+
+## Syntax
+
+```bash
+GEOHASH key member [member ...]
+```
+
+## Parameters
+
+| Parameter | Description                                                      | Type   | Required |
+| --------- | ---------------------------------------------------------------- | ------ | -------- |
+| key       | The name of the sorted set containing geospatial data.           | string | Yes      |
+| member    | One or more members whose Geohash representations are requested. | string | Yes      |
+
+## Return Values
+
+| Condition                                   | Return Value                                          |
+| ------------------------------------------- | ----------------------------------------------------- |
+| Geohash representation for valid members.   | A string representing the Geohash of each member.    |
+| Non-existent member in the specified key.   | `(nil)` for that member.                             |
+| Incorrect Argument Count                    | `ERR wrong number of arguments for 'geohash' command` |
+| Non-existent or invalid key type.           | `WRONGTYPE Operation against a key holding the wrong kind of value`  |
+
+## Behaviour
+
+When the GEOHASH command is issued, DiceDB performs the following steps:
+
+1. Checks if the key exists and corresponds to a valid geospatial dataset.  
+2. Verifies the presence of each specified member within the dataset.  
+3. For each member:
+   - If the member exists, its Geohash representation is returned.
+   - If the member does not exist, `(nil)` is returned.  
+4. Returns the results as an array of strings or nil values, maintaining the order of input members.
+
+## Errors
+
+1. **Wrong Number of Arguments**
+   - **Error Message:** (error) ERR wrong number of arguments for 'geohash' command  
+   - Occurs when the command is executed without a key or member(s).  
+
+2. **Key Does Not Exist or Is of Wrong Type**  
+   - **Error Message:** (error) WRONGTYPE Operation against a key holding the wrong kind of value
+   - Occurs when the specified key does not exist or is not a sorted set.  
+
+3. **Member Does Not Exist**
+   - **Error Message:** Returns `(nil)` for non-existent members.  
+   - Occurs when a member is specified but not found under the given key.  
+
+## Example Usage
+
+Here are a few examples demonstrating the usage of the GEOHASH command:
+
+### Example: Retrieve Geohash for Existing Members
+
+```bash
+127.0.0.1:7379> GEOADD locations 13.361389 38.115556 "Palermo" 15.087269 37.502669 "Catania"
+2
+127.0.0.1:7379> GEOHASH locations Palermo Catania
+1) "sqc8b49rny"
+2) "sq9sm17147"
+```
+
+### Example: Retrieve Geohash for a Non-Existent Member
+
+```bash
+127.0.0.1:7379> GEOHASH locations Venice
+(nil)
+```
+
+### Example: Retrieve Geohash with a Non-Existent Key
+
+```bash
+127.0.0.1:7379> GEOHASH points Palermo
+(error) WRONGTYPE Operation against a key holding the wrong kind of value
+```
+
+### Example: Retrieve Geohash with Missing Arguments
+
+```bash
+127.0.0.1:7379> GEOHASH
+(error) ERR wrong number of arguments for 'geohash' command
+```
+
+## Notes
+
+- The returned Geohash strings are encoded representations of the geographic locations stored in the sorted set.
+- Geohash precision is influenced by the DiceDB implementation and is typically sufficient for most spatial queries.